Research-Methodology

Literature review sources

Sources for literature review can be divided into three categories as illustrated in table below. In your dissertation you will need to use all three categories of literature review sources:

Sources for literature review and examples

Generally, your literature review should integrate a wide range of sources such as:

  • Books . Textbooks remain as the most important source to find models and theories related to the research area. Research the most respected authorities in your selected research area and find the latest editions of books authored by them. For example, in the area of marketing the most notable authors include Philip Kotler, Seth Godin, Malcolm Gladwell, Emanuel Rosen and others.
  • Magazines . Industry-specific magazines are usually rich in scholarly articles and they can be effective source to learn about the latest trends and developments in the research area. Reading industry magazines can be the most enjoyable part of the literature review, assuming that your selected research area represents an area of your personal and professional interests, which should be the case anyways.
  • Newspapers can be referred to as the main source of up-to-date news about the latest events related to the research area. However, the proportion of the use of newspapers in literature review is recommended to be less compared to alternative sources of secondary data such as books and magazines. This is due to the fact that newspaper articles mainly lack depth of analyses and discussions.
  • Online articles . You can find online versions of all of the above sources. However, note that the levels of reliability of online articles can be highly compromised depending on the source due to the high levels of ease with which articles can be published online. Opinions offered in a wide range of online discussion blogs cannot be usually used in literature review. Similarly, dissertation assessors are not keen to appreciate references to a wide range of blogs, unless articles in these blogs are authored by respected authorities in the research area.

Your secondary data sources may comprise certain amount of grey literature as well. The term grey literature refers to type of literature produced by government, academics, business and industry in print and electronic formats, which is not controlled by commercial publishers. It is called ‘grey’ because the status of the information in grey literature is not certain. In other words, any publication that has not been peer reviewed for publication is grey literature.

The necessity to use grey literature arises when there is no enough peer reviewed publications are available for the subject of your study.

Literature review sources

John Dudovskiy

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Organizing Your Social Sciences Research Paper

  • 5. The Literature Review
  • Purpose of Guide
  • Design Flaws to Avoid
  • Independent and Dependent Variables
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  • Narrowing a Topic Idea
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  • Common Grammar Mistakes
  • Writing Concisely
  • Avoiding Plagiarism
  • Footnotes or Endnotes?
  • Further Readings
  • Generative AI and Writing
  • USC Libraries Tutorials and Other Guides
  • Bibliography

A literature review surveys prior research published in books, scholarly articles, and any other sources relevant to a particular issue, area of research, or theory, and by so doing, provides a description, summary, and critical evaluation of these works in relation to the research problem being investigated. Literature reviews are designed to provide an overview of sources you have used in researching a particular topic and to demonstrate to your readers how your research fits within existing scholarship about the topic.

Fink, Arlene. Conducting Research Literature Reviews: From the Internet to Paper . Fourth edition. Thousand Oaks, CA: SAGE, 2014.

Importance of a Good Literature Review

A literature review may consist of simply a summary of key sources, but in the social sciences, a literature review usually has an organizational pattern and combines both summary and synthesis, often within specific conceptual categories . A summary is a recap of the important information of the source, but a synthesis is a re-organization, or a reshuffling, of that information in a way that informs how you are planning to investigate a research problem. The analytical features of a literature review might:

  • Give a new interpretation of old material or combine new with old interpretations,
  • Trace the intellectual progression of the field, including major debates,
  • Depending on the situation, evaluate the sources and advise the reader on the most pertinent or relevant research, or
  • Usually in the conclusion of a literature review, identify where gaps exist in how a problem has been researched to date.

Given this, the purpose of a literature review is to:

  • Place each work in the context of its contribution to understanding the research problem being studied.
  • Describe the relationship of each work to the others under consideration.
  • Identify new ways to interpret prior research.
  • Reveal any gaps that exist in the literature.
  • Resolve conflicts amongst seemingly contradictory previous studies.
  • Identify areas of prior scholarship to prevent duplication of effort.
  • Point the way in fulfilling a need for additional research.
  • Locate your own research within the context of existing literature [very important].

Fink, Arlene. Conducting Research Literature Reviews: From the Internet to Paper. 2nd ed. Thousand Oaks, CA: Sage, 2005; Hart, Chris. Doing a Literature Review: Releasing the Social Science Research Imagination . Thousand Oaks, CA: Sage Publications, 1998; Jesson, Jill. Doing Your Literature Review: Traditional and Systematic Techniques . Los Angeles, CA: SAGE, 2011; Knopf, Jeffrey W. "Doing a Literature Review." PS: Political Science and Politics 39 (January 2006): 127-132; Ridley, Diana. The Literature Review: A Step-by-Step Guide for Students . 2nd ed. Los Angeles, CA: SAGE, 2012.

Types of Literature Reviews

It is important to think of knowledge in a given field as consisting of three layers. First, there are the primary studies that researchers conduct and publish. Second are the reviews of those studies that summarize and offer new interpretations built from and often extending beyond the primary studies. Third, there are the perceptions, conclusions, opinion, and interpretations that are shared informally among scholars that become part of the body of epistemological traditions within the field.

In composing a literature review, it is important to note that it is often this third layer of knowledge that is cited as "true" even though it often has only a loose relationship to the primary studies and secondary literature reviews. Given this, while literature reviews are designed to provide an overview and synthesis of pertinent sources you have explored, there are a number of approaches you could adopt depending upon the type of analysis underpinning your study.

Argumentative Review This form examines literature selectively in order to support or refute an argument, deeply embedded assumption, or philosophical problem already established in the literature. The purpose is to develop a body of literature that establishes a contrarian viewpoint. Given the value-laden nature of some social science research [e.g., educational reform; immigration control], argumentative approaches to analyzing the literature can be a legitimate and important form of discourse. However, note that they can also introduce problems of bias when they are used to make summary claims of the sort found in systematic reviews [see below].

Integrative Review Considered a form of research that reviews, critiques, and synthesizes representative literature on a topic in an integrated way such that new frameworks and perspectives on the topic are generated. The body of literature includes all studies that address related or identical hypotheses or research problems. A well-done integrative review meets the same standards as primary research in regard to clarity, rigor, and replication. This is the most common form of review in the social sciences.

Historical Review Few things rest in isolation from historical precedent. Historical literature reviews focus on examining research throughout a period of time, often starting with the first time an issue, concept, theory, phenomena emerged in the literature, then tracing its evolution within the scholarship of a discipline. The purpose is to place research in a historical context to show familiarity with state-of-the-art developments and to identify the likely directions for future research.

Methodological Review A review does not always focus on what someone said [findings], but how they came about saying what they say [method of analysis]. Reviewing methods of analysis provides a framework of understanding at different levels [i.e. those of theory, substantive fields, research approaches, and data collection and analysis techniques], how researchers draw upon a wide variety of knowledge ranging from the conceptual level to practical documents for use in fieldwork in the areas of ontological and epistemological consideration, quantitative and qualitative integration, sampling, interviewing, data collection, and data analysis. This approach helps highlight ethical issues which you should be aware of and consider as you go through your own study.

Systematic Review This form consists of an overview of existing evidence pertinent to a clearly formulated research question, which uses pre-specified and standardized methods to identify and critically appraise relevant research, and to collect, report, and analyze data from the studies that are included in the review. The goal is to deliberately document, critically evaluate, and summarize scientifically all of the research about a clearly defined research problem . Typically it focuses on a very specific empirical question, often posed in a cause-and-effect form, such as "To what extent does A contribute to B?" This type of literature review is primarily applied to examining prior research studies in clinical medicine and allied health fields, but it is increasingly being used in the social sciences.

Theoretical Review The purpose of this form is to examine the corpus of theory that has accumulated in regard to an issue, concept, theory, phenomena. The theoretical literature review helps to establish what theories already exist, the relationships between them, to what degree the existing theories have been investigated, and to develop new hypotheses to be tested. Often this form is used to help establish a lack of appropriate theories or reveal that current theories are inadequate for explaining new or emerging research problems. The unit of analysis can focus on a theoretical concept or a whole theory or framework.

NOTE : Most often the literature review will incorporate some combination of types. For example, a review that examines literature supporting or refuting an argument, assumption, or philosophical problem related to the research problem will also need to include writing supported by sources that establish the history of these arguments in the literature.

Baumeister, Roy F. and Mark R. Leary. "Writing Narrative Literature Reviews."  Review of General Psychology 1 (September 1997): 311-320; Mark R. Fink, Arlene. Conducting Research Literature Reviews: From the Internet to Paper . 2nd ed. Thousand Oaks, CA: Sage, 2005; Hart, Chris. Doing a Literature Review: Releasing the Social Science Research Imagination . Thousand Oaks, CA: Sage Publications, 1998; Kennedy, Mary M. "Defining a Literature." Educational Researcher 36 (April 2007): 139-147; Petticrew, Mark and Helen Roberts. Systematic Reviews in the Social Sciences: A Practical Guide . Malden, MA: Blackwell Publishers, 2006; Torracro, Richard. "Writing Integrative Literature Reviews: Guidelines and Examples." Human Resource Development Review 4 (September 2005): 356-367; Rocco, Tonette S. and Maria S. Plakhotnik. "Literature Reviews, Conceptual Frameworks, and Theoretical Frameworks: Terms, Functions, and Distinctions." Human Ressource Development Review 8 (March 2008): 120-130; Sutton, Anthea. Systematic Approaches to a Successful Literature Review . Los Angeles, CA: Sage Publications, 2016.

Structure and Writing Style

I.  Thinking About Your Literature Review

The structure of a literature review should include the following in support of understanding the research problem :

  • An overview of the subject, issue, or theory under consideration, along with the objectives of the literature review,
  • Division of works under review into themes or categories [e.g. works that support a particular position, those against, and those offering alternative approaches entirely],
  • An explanation of how each work is similar to and how it varies from the others,
  • Conclusions as to which pieces are best considered in their argument, are most convincing of their opinions, and make the greatest contribution to the understanding and development of their area of research.

The critical evaluation of each work should consider :

  • Provenance -- what are the author's credentials? Are the author's arguments supported by evidence [e.g. primary historical material, case studies, narratives, statistics, recent scientific findings]?
  • Methodology -- were the techniques used to identify, gather, and analyze the data appropriate to addressing the research problem? Was the sample size appropriate? Were the results effectively interpreted and reported?
  • Objectivity -- is the author's perspective even-handed or prejudicial? Is contrary data considered or is certain pertinent information ignored to prove the author's point?
  • Persuasiveness -- which of the author's theses are most convincing or least convincing?
  • Validity -- are the author's arguments and conclusions convincing? Does the work ultimately contribute in any significant way to an understanding of the subject?

II.  Development of the Literature Review

Four Basic Stages of Writing 1.  Problem formulation -- which topic or field is being examined and what are its component issues? 2.  Literature search -- finding materials relevant to the subject being explored. 3.  Data evaluation -- determining which literature makes a significant contribution to the understanding of the topic. 4.  Analysis and interpretation -- discussing the findings and conclusions of pertinent literature.

Consider the following issues before writing the literature review: Clarify If your assignment is not specific about what form your literature review should take, seek clarification from your professor by asking these questions: 1.  Roughly how many sources would be appropriate to include? 2.  What types of sources should I review (books, journal articles, websites; scholarly versus popular sources)? 3.  Should I summarize, synthesize, or critique sources by discussing a common theme or issue? 4.  Should I evaluate the sources in any way beyond evaluating how they relate to understanding the research problem? 5.  Should I provide subheadings and other background information, such as definitions and/or a history? Find Models Use the exercise of reviewing the literature to examine how authors in your discipline or area of interest have composed their literature review sections. Read them to get a sense of the types of themes you might want to look for in your own research or to identify ways to organize your final review. The bibliography or reference section of sources you've already read, such as required readings in the course syllabus, are also excellent entry points into your own research. Narrow the Topic The narrower your topic, the easier it will be to limit the number of sources you need to read in order to obtain a good survey of relevant resources. Your professor will probably not expect you to read everything that's available about the topic, but you'll make the act of reviewing easier if you first limit scope of the research problem. A good strategy is to begin by searching the USC Libraries Catalog for recent books about the topic and review the table of contents for chapters that focuses on specific issues. You can also review the indexes of books to find references to specific issues that can serve as the focus of your research. For example, a book surveying the history of the Israeli-Palestinian conflict may include a chapter on the role Egypt has played in mediating the conflict, or look in the index for the pages where Egypt is mentioned in the text. Consider Whether Your Sources are Current Some disciplines require that you use information that is as current as possible. This is particularly true in disciplines in medicine and the sciences where research conducted becomes obsolete very quickly as new discoveries are made. However, when writing a review in the social sciences, a survey of the history of the literature may be required. In other words, a complete understanding the research problem requires you to deliberately examine how knowledge and perspectives have changed over time. Sort through other current bibliographies or literature reviews in the field to get a sense of what your discipline expects. You can also use this method to explore what is considered by scholars to be a "hot topic" and what is not.

III.  Ways to Organize Your Literature Review

Chronology of Events If your review follows the chronological method, you could write about the materials according to when they were published. This approach should only be followed if a clear path of research building on previous research can be identified and that these trends follow a clear chronological order of development. For example, a literature review that focuses on continuing research about the emergence of German economic power after the fall of the Soviet Union. By Publication Order your sources by publication chronology, then, only if the order demonstrates a more important trend. For instance, you could order a review of literature on environmental studies of brown fields if the progression revealed, for example, a change in the soil collection practices of the researchers who wrote and/or conducted the studies. Thematic [“conceptual categories”] A thematic literature review is the most common approach to summarizing prior research in the social and behavioral sciences. Thematic reviews are organized around a topic or issue, rather than the progression of time, although the progression of time may still be incorporated into a thematic review. For example, a review of the Internet’s impact on American presidential politics could focus on the development of online political satire. While the study focuses on one topic, the Internet’s impact on American presidential politics, it would still be organized chronologically reflecting technological developments in media. The difference in this example between a "chronological" and a "thematic" approach is what is emphasized the most: themes related to the role of the Internet in presidential politics. Note that more authentic thematic reviews tend to break away from chronological order. A review organized in this manner would shift between time periods within each section according to the point being made. Methodological A methodological approach focuses on the methods utilized by the researcher. For the Internet in American presidential politics project, one methodological approach would be to look at cultural differences between the portrayal of American presidents on American, British, and French websites. Or the review might focus on the fundraising impact of the Internet on a particular political party. A methodological scope will influence either the types of documents in the review or the way in which these documents are discussed.

Other Sections of Your Literature Review Once you've decided on the organizational method for your literature review, the sections you need to include in the paper should be easy to figure out because they arise from your organizational strategy. In other words, a chronological review would have subsections for each vital time period; a thematic review would have subtopics based upon factors that relate to the theme or issue. However, sometimes you may need to add additional sections that are necessary for your study, but do not fit in the organizational strategy of the body. What other sections you include in the body is up to you. However, only include what is necessary for the reader to locate your study within the larger scholarship about the research problem.

Here are examples of other sections, usually in the form of a single paragraph, you may need to include depending on the type of review you write:

  • Current Situation : Information necessary to understand the current topic or focus of the literature review.
  • Sources Used : Describes the methods and resources [e.g., databases] you used to identify the literature you reviewed.
  • History : The chronological progression of the field, the research literature, or an idea that is necessary to understand the literature review, if the body of the literature review is not already a chronology.
  • Selection Methods : Criteria you used to select (and perhaps exclude) sources in your literature review. For instance, you might explain that your review includes only peer-reviewed [i.e., scholarly] sources.
  • Standards : Description of the way in which you present your information.
  • Questions for Further Research : What questions about the field has the review sparked? How will you further your research as a result of the review?

IV.  Writing Your Literature Review

Once you've settled on how to organize your literature review, you're ready to write each section. When writing your review, keep in mind these issues.

Use Evidence A literature review section is, in this sense, just like any other academic research paper. Your interpretation of the available sources must be backed up with evidence [citations] that demonstrates that what you are saying is valid. Be Selective Select only the most important points in each source to highlight in the review. The type of information you choose to mention should relate directly to the research problem, whether it is thematic, methodological, or chronological. Related items that provide additional information, but that are not key to understanding the research problem, can be included in a list of further readings . Use Quotes Sparingly Some short quotes are appropriate if you want to emphasize a point, or if what an author stated cannot be easily paraphrased. Sometimes you may need to quote certain terminology that was coined by the author, is not common knowledge, or taken directly from the study. Do not use extensive quotes as a substitute for using your own words in reviewing the literature. Summarize and Synthesize Remember to summarize and synthesize your sources within each thematic paragraph as well as throughout the review. Recapitulate important features of a research study, but then synthesize it by rephrasing the study's significance and relating it to your own work and the work of others. Keep Your Own Voice While the literature review presents others' ideas, your voice [the writer's] should remain front and center. For example, weave references to other sources into what you are writing but maintain your own voice by starting and ending the paragraph with your own ideas and wording. Use Caution When Paraphrasing When paraphrasing a source that is not your own, be sure to represent the author's information or opinions accurately and in your own words. Even when paraphrasing an author’s work, you still must provide a citation to that work.

V.  Common Mistakes to Avoid

These are the most common mistakes made in reviewing social science research literature.

  • Sources in your literature review do not clearly relate to the research problem;
  • You do not take sufficient time to define and identify the most relevant sources to use in the literature review related to the research problem;
  • Relies exclusively on secondary analytical sources rather than including relevant primary research studies or data;
  • Uncritically accepts another researcher's findings and interpretations as valid, rather than examining critically all aspects of the research design and analysis;
  • Does not describe the search procedures that were used in identifying the literature to review;
  • Reports isolated statistical results rather than synthesizing them in chi-squared or meta-analytic methods; and,
  • Only includes research that validates assumptions and does not consider contrary findings and alternative interpretations found in the literature.

Cook, Kathleen E. and Elise Murowchick. “Do Literature Review Skills Transfer from One Course to Another?” Psychology Learning and Teaching 13 (March 2014): 3-11; Fink, Arlene. Conducting Research Literature Reviews: From the Internet to Paper . 2nd ed. Thousand Oaks, CA: Sage, 2005; Hart, Chris. Doing a Literature Review: Releasing the Social Science Research Imagination . Thousand Oaks, CA: Sage Publications, 1998; Jesson, Jill. Doing Your Literature Review: Traditional and Systematic Techniques . London: SAGE, 2011; Literature Review Handout. Online Writing Center. Liberty University; Literature Reviews. The Writing Center. University of North Carolina; Onwuegbuzie, Anthony J. and Rebecca Frels. Seven Steps to a Comprehensive Literature Review: A Multimodal and Cultural Approach . Los Angeles, CA: SAGE, 2016; Ridley, Diana. The Literature Review: A Step-by-Step Guide for Students . 2nd ed. Los Angeles, CA: SAGE, 2012; Randolph, Justus J. “A Guide to Writing the Dissertation Literature Review." Practical Assessment, Research, and Evaluation. vol. 14, June 2009; Sutton, Anthea. Systematic Approaches to a Successful Literature Review . Los Angeles, CA: Sage Publications, 2016; Taylor, Dena. The Literature Review: A Few Tips On Conducting It. University College Writing Centre. University of Toronto; Writing a Literature Review. Academic Skills Centre. University of Canberra.

Writing Tip

Break Out of Your Disciplinary Box!

Thinking interdisciplinarily about a research problem can be a rewarding exercise in applying new ideas, theories, or concepts to an old problem. For example, what might cultural anthropologists say about the continuing conflict in the Middle East? In what ways might geographers view the need for better distribution of social service agencies in large cities than how social workers might study the issue? You don’t want to substitute a thorough review of core research literature in your discipline for studies conducted in other fields of study. However, particularly in the social sciences, thinking about research problems from multiple vectors is a key strategy for finding new solutions to a problem or gaining a new perspective. Consult with a librarian about identifying research databases in other disciplines; almost every field of study has at least one comprehensive database devoted to indexing its research literature.

Frodeman, Robert. The Oxford Handbook of Interdisciplinarity . New York: Oxford University Press, 2010.

Another Writing Tip

Don't Just Review for Content!

While conducting a review of the literature, maximize the time you devote to writing this part of your paper by thinking broadly about what you should be looking for and evaluating. Review not just what scholars are saying, but how are they saying it. Some questions to ask:

  • How are they organizing their ideas?
  • What methods have they used to study the problem?
  • What theories have been used to explain, predict, or understand their research problem?
  • What sources have they cited to support their conclusions?
  • How have they used non-textual elements [e.g., charts, graphs, figures, etc.] to illustrate key points?

When you begin to write your literature review section, you'll be glad you dug deeper into how the research was designed and constructed because it establishes a means for developing more substantial analysis and interpretation of the research problem.

Hart, Chris. Doing a Literature Review: Releasing the Social Science Research Imagination . Thousand Oaks, CA: Sage Publications, 1 998.

Yet Another Writing Tip

When Do I Know I Can Stop Looking and Move On?

Here are several strategies you can utilize to assess whether you've thoroughly reviewed the literature:

  • Look for repeating patterns in the research findings . If the same thing is being said, just by different people, then this likely demonstrates that the research problem has hit a conceptual dead end. At this point consider: Does your study extend current research?  Does it forge a new path? Or, does is merely add more of the same thing being said?
  • Look at sources the authors cite to in their work . If you begin to see the same researchers cited again and again, then this is often an indication that no new ideas have been generated to address the research problem.
  • Search Google Scholar to identify who has subsequently cited leading scholars already identified in your literature review [see next sub-tab]. This is called citation tracking and there are a number of sources that can help you identify who has cited whom, particularly scholars from outside of your discipline. Here again, if the same authors are being cited again and again, this may indicate no new literature has been written on the topic.

Onwuegbuzie, Anthony J. and Rebecca Frels. Seven Steps to a Comprehensive Literature Review: A Multimodal and Cultural Approach . Los Angeles, CA: Sage, 2016; Sutton, Anthea. Systematic Approaches to a Successful Literature Review . Los Angeles, CA: Sage Publications, 2016.

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Writing a Literature Review

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A literature review is a document or section of a document that collects key sources on a topic and discusses those sources in conversation with each other (also called synthesis ). The lit review is an important genre in many disciplines, not just literature (i.e., the study of works of literature such as novels and plays). When we say “literature review” or refer to “the literature,” we are talking about the research ( scholarship ) in a given field. You will often see the terms “the research,” “the scholarship,” and “the literature” used mostly interchangeably.

Where, when, and why would I write a lit review?

There are a number of different situations where you might write a literature review, each with slightly different expectations; different disciplines, too, have field-specific expectations for what a literature review is and does. For instance, in the humanities, authors might include more overt argumentation and interpretation of source material in their literature reviews, whereas in the sciences, authors are more likely to report study designs and results in their literature reviews; these differences reflect these disciplines’ purposes and conventions in scholarship. You should always look at examples from your own discipline and talk to professors or mentors in your field to be sure you understand your discipline’s conventions, for literature reviews as well as for any other genre.

A literature review can be a part of a research paper or scholarly article, usually falling after the introduction and before the research methods sections. In these cases, the lit review just needs to cover scholarship that is important to the issue you are writing about; sometimes it will also cover key sources that informed your research methodology.

Lit reviews can also be standalone pieces, either as assignments in a class or as publications. In a class, a lit review may be assigned to help students familiarize themselves with a topic and with scholarship in their field, get an idea of the other researchers working on the topic they’re interested in, find gaps in existing research in order to propose new projects, and/or develop a theoretical framework and methodology for later research. As a publication, a lit review usually is meant to help make other scholars’ lives easier by collecting and summarizing, synthesizing, and analyzing existing research on a topic. This can be especially helpful for students or scholars getting into a new research area, or for directing an entire community of scholars toward questions that have not yet been answered.

What are the parts of a lit review?

Most lit reviews use a basic introduction-body-conclusion structure; if your lit review is part of a larger paper, the introduction and conclusion pieces may be just a few sentences while you focus most of your attention on the body. If your lit review is a standalone piece, the introduction and conclusion take up more space and give you a place to discuss your goals, research methods, and conclusions separately from where you discuss the literature itself.

Introduction:

  • An introductory paragraph that explains what your working topic and thesis is
  • A forecast of key topics or texts that will appear in the review
  • Potentially, a description of how you found sources and how you analyzed them for inclusion and discussion in the review (more often found in published, standalone literature reviews than in lit review sections in an article or research paper)
  • Summarize and synthesize: Give an overview of the main points of each source and combine them into a coherent whole
  • Analyze and interpret: Don’t just paraphrase other researchers – add your own interpretations where possible, discussing the significance of findings in relation to the literature as a whole
  • Critically Evaluate: Mention the strengths and weaknesses of your sources
  • Write in well-structured paragraphs: Use transition words and topic sentence to draw connections, comparisons, and contrasts.

Conclusion:

  • Summarize the key findings you have taken from the literature and emphasize their significance
  • Connect it back to your primary research question

How should I organize my lit review?

Lit reviews can take many different organizational patterns depending on what you are trying to accomplish with the review. Here are some examples:

  • Chronological : The simplest approach is to trace the development of the topic over time, which helps familiarize the audience with the topic (for instance if you are introducing something that is not commonly known in your field). If you choose this strategy, be careful to avoid simply listing and summarizing sources in order. Try to analyze the patterns, turning points, and key debates that have shaped the direction of the field. Give your interpretation of how and why certain developments occurred (as mentioned previously, this may not be appropriate in your discipline — check with a teacher or mentor if you’re unsure).
  • Thematic : If you have found some recurring central themes that you will continue working with throughout your piece, you can organize your literature review into subsections that address different aspects of the topic. For example, if you are reviewing literature about women and religion, key themes can include the role of women in churches and the religious attitude towards women.
  • Qualitative versus quantitative research
  • Empirical versus theoretical scholarship
  • Divide the research by sociological, historical, or cultural sources
  • Theoretical : In many humanities articles, the literature review is the foundation for the theoretical framework. You can use it to discuss various theories, models, and definitions of key concepts. You can argue for the relevance of a specific theoretical approach or combine various theorical concepts to create a framework for your research.

What are some strategies or tips I can use while writing my lit review?

Any lit review is only as good as the research it discusses; make sure your sources are well-chosen and your research is thorough. Don’t be afraid to do more research if you discover a new thread as you’re writing. More info on the research process is available in our "Conducting Research" resources .

As you’re doing your research, create an annotated bibliography ( see our page on the this type of document ). Much of the information used in an annotated bibliography can be used also in a literature review, so you’ll be not only partially drafting your lit review as you research, but also developing your sense of the larger conversation going on among scholars, professionals, and any other stakeholders in your topic.

Usually you will need to synthesize research rather than just summarizing it. This means drawing connections between sources to create a picture of the scholarly conversation on a topic over time. Many student writers struggle to synthesize because they feel they don’t have anything to add to the scholars they are citing; here are some strategies to help you:

  • It often helps to remember that the point of these kinds of syntheses is to show your readers how you understand your research, to help them read the rest of your paper.
  • Writing teachers often say synthesis is like hosting a dinner party: imagine all your sources are together in a room, discussing your topic. What are they saying to each other?
  • Look at the in-text citations in each paragraph. Are you citing just one source for each paragraph? This usually indicates summary only. When you have multiple sources cited in a paragraph, you are more likely to be synthesizing them (not always, but often
  • Read more about synthesis here.

The most interesting literature reviews are often written as arguments (again, as mentioned at the beginning of the page, this is discipline-specific and doesn’t work for all situations). Often, the literature review is where you can establish your research as filling a particular gap or as relevant in a particular way. You have some chance to do this in your introduction in an article, but the literature review section gives a more extended opportunity to establish the conversation in the way you would like your readers to see it. You can choose the intellectual lineage you would like to be part of and whose definitions matter most to your thinking (mostly humanities-specific, but this goes for sciences as well). In addressing these points, you argue for your place in the conversation, which tends to make the lit review more compelling than a simple reporting of other sources.

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What is a Literature Review? | Guide, Template, & Examples

Published on 22 February 2022 by Shona McCombes . Revised on 7 June 2022.

What is a literature review? A literature review is a survey of scholarly sources on a specific topic. It provides an overview of current knowledge, allowing you to identify relevant theories, methods, and gaps in the existing research.

There are five key steps to writing a literature review:

  • Search for relevant literature
  • Evaluate sources
  • Identify themes, debates and gaps
  • Outline the structure
  • Write your literature review

A good literature review doesn’t just summarise sources – it analyses, synthesises, and critically evaluates to give a clear picture of the state of knowledge on the subject.

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Table of contents

Why write a literature review, examples of literature reviews, step 1: search for relevant literature, step 2: evaluate and select sources, step 3: identify themes, debates and gaps, step 4: outline your literature review’s structure, step 5: write your literature review, frequently asked questions about literature reviews, introduction.

  • Quick Run-through
  • Step 1 & 2

When you write a dissertation or thesis, you will have to conduct a literature review to situate your research within existing knowledge. The literature review gives you a chance to:

  • Demonstrate your familiarity with the topic and scholarly context
  • Develop a theoretical framework and methodology for your research
  • Position yourself in relation to other researchers and theorists
  • Show how your dissertation addresses a gap or contributes to a debate

You might also have to write a literature review as a stand-alone assignment. In this case, the purpose is to evaluate the current state of research and demonstrate your knowledge of scholarly debates around a topic.

The content will look slightly different in each case, but the process of conducting a literature review follows the same steps. We’ve written a step-by-step guide that you can follow below.

Literature review guide

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Writing literature reviews can be quite challenging! A good starting point could be to look at some examples, depending on what kind of literature review you’d like to write.

  • Example literature review #1: “Why Do People Migrate? A Review of the Theoretical Literature” ( Theoretical literature review about the development of economic migration theory from the 1950s to today.)
  • Example literature review #2: “Literature review as a research methodology: An overview and guidelines” ( Methodological literature review about interdisciplinary knowledge acquisition and production.)
  • Example literature review #3: “The Use of Technology in English Language Learning: A Literature Review” ( Thematic literature review about the effects of technology on language acquisition.)
  • Example literature review #4: “Learners’ Listening Comprehension Difficulties in English Language Learning: A Literature Review” ( Chronological literature review about how the concept of listening skills has changed over time.)

You can also check out our templates with literature review examples and sample outlines at the links below.

Download Word doc Download Google doc

Before you begin searching for literature, you need a clearly defined topic .

If you are writing the literature review section of a dissertation or research paper, you will search for literature related to your research objectives and questions .

If you are writing a literature review as a stand-alone assignment, you will have to choose a focus and develop a central question to direct your search. Unlike a dissertation research question, this question has to be answerable without collecting original data. You should be able to answer it based only on a review of existing publications.

Make a list of keywords

Start by creating a list of keywords related to your research topic. Include each of the key concepts or variables you’re interested in, and list any synonyms and related terms. You can add to this list if you discover new keywords in the process of your literature search.

  • Social media, Facebook, Instagram, Twitter, Snapchat, TikTok
  • Body image, self-perception, self-esteem, mental health
  • Generation Z, teenagers, adolescents, youth

Search for relevant sources

Use your keywords to begin searching for sources. Some databases to search for journals and articles include:

  • Your university’s library catalogue
  • Google Scholar
  • Project Muse (humanities and social sciences)
  • Medline (life sciences and biomedicine)
  • EconLit (economics)
  • Inspec (physics, engineering and computer science)

You can use boolean operators to help narrow down your search:

Read the abstract to find out whether an article is relevant to your question. When you find a useful book or article, you can check the bibliography to find other relevant sources.

To identify the most important publications on your topic, take note of recurring citations. If the same authors, books or articles keep appearing in your reading, make sure to seek them out.

You probably won’t be able to read absolutely everything that has been written on the topic – you’ll have to evaluate which sources are most relevant to your questions.

For each publication, ask yourself:

  • What question or problem is the author addressing?
  • What are the key concepts and how are they defined?
  • What are the key theories, models and methods? Does the research use established frameworks or take an innovative approach?
  • What are the results and conclusions of the study?
  • How does the publication relate to other literature in the field? Does it confirm, add to, or challenge established knowledge?
  • How does the publication contribute to your understanding of the topic? What are its key insights and arguments?
  • What are the strengths and weaknesses of the research?

Make sure the sources you use are credible, and make sure you read any landmark studies and major theories in your field of research.

You can find out how many times an article has been cited on Google Scholar – a high citation count means the article has been influential in the field, and should certainly be included in your literature review.

The scope of your review will depend on your topic and discipline: in the sciences you usually only review recent literature, but in the humanities you might take a long historical perspective (for example, to trace how a concept has changed in meaning over time).

Remember that you can use our template to summarise and evaluate sources you’re thinking about using!

Take notes and cite your sources

As you read, you should also begin the writing process. Take notes that you can later incorporate into the text of your literature review.

It’s important to keep track of your sources with references to avoid plagiarism . It can be helpful to make an annotated bibliography, where you compile full reference information and write a paragraph of summary and analysis for each source. This helps you remember what you read and saves time later in the process.

You can use our free APA Reference Generator for quick, correct, consistent citations.

To begin organising your literature review’s argument and structure, you need to understand the connections and relationships between the sources you’ve read. Based on your reading and notes, you can look for:

  • Trends and patterns (in theory, method or results): do certain approaches become more or less popular over time?
  • Themes: what questions or concepts recur across the literature?
  • Debates, conflicts and contradictions: where do sources disagree?
  • Pivotal publications: are there any influential theories or studies that changed the direction of the field?
  • Gaps: what is missing from the literature? Are there weaknesses that need to be addressed?

This step will help you work out the structure of your literature review and (if applicable) show how your own research will contribute to existing knowledge.

  • Most research has focused on young women.
  • There is an increasing interest in the visual aspects of social media.
  • But there is still a lack of robust research on highly-visual platforms like Instagram and Snapchat – this is a gap that you could address in your own research.

There are various approaches to organising the body of a literature review. You should have a rough idea of your strategy before you start writing.

Depending on the length of your literature review, you can combine several of these strategies (for example, your overall structure might be thematic, but each theme is discussed chronologically).

Chronological

The simplest approach is to trace the development of the topic over time. However, if you choose this strategy, be careful to avoid simply listing and summarising sources in order.

Try to analyse patterns, turning points and key debates that have shaped the direction of the field. Give your interpretation of how and why certain developments occurred.

If you have found some recurring central themes, you can organise your literature review into subsections that address different aspects of the topic.

For example, if you are reviewing literature about inequalities in migrant health outcomes, key themes might include healthcare policy, language barriers, cultural attitudes, legal status, and economic access.

Methodological

If you draw your sources from different disciplines or fields that use a variety of research methods , you might want to compare the results and conclusions that emerge from different approaches. For example:

  • Look at what results have emerged in qualitative versus quantitative research
  • Discuss how the topic has been approached by empirical versus theoretical scholarship
  • Divide the literature into sociological, historical, and cultural sources

Theoretical

A literature review is often the foundation for a theoretical framework . You can use it to discuss various theories, models, and definitions of key concepts.

You might argue for the relevance of a specific theoretical approach, or combine various theoretical concepts to create a framework for your research.

Like any other academic text, your literature review should have an introduction , a main body, and a conclusion . What you include in each depends on the objective of your literature review.

The introduction should clearly establish the focus and purpose of the literature review.

If you are writing the literature review as part of your dissertation or thesis, reiterate your central problem or research question and give a brief summary of the scholarly context. You can emphasise the timeliness of the topic (“many recent studies have focused on the problem of x”) or highlight a gap in the literature (“while there has been much research on x, few researchers have taken y into consideration”).

Depending on the length of your literature review, you might want to divide the body into subsections. You can use a subheading for each theme, time period, or methodological approach.

As you write, make sure to follow these tips:

  • Summarise and synthesise: give an overview of the main points of each source and combine them into a coherent whole.
  • Analyse and interpret: don’t just paraphrase other researchers – add your own interpretations, discussing the significance of findings in relation to the literature as a whole.
  • Critically evaluate: mention the strengths and weaknesses of your sources.
  • Write in well-structured paragraphs: use transitions and topic sentences to draw connections, comparisons and contrasts.

In the conclusion, you should summarise the key findings you have taken from the literature and emphasise their significance.

If the literature review is part of your dissertation or thesis, reiterate how your research addresses gaps and contributes new knowledge, or discuss how you have drawn on existing theories and methods to build a framework for your research. This can lead directly into your methodology section.

A literature review is a survey of scholarly sources (such as books, journal articles, and theses) related to a specific topic or research question .

It is often written as part of a dissertation , thesis, research paper , or proposal .

There are several reasons to conduct a literature review at the beginning of a research project:

  • To familiarise yourself with the current state of knowledge on your topic
  • To ensure that you’re not just repeating what others have already done
  • To identify gaps in knowledge and unresolved problems that your research can address
  • To develop your theoretical framework and methodology
  • To provide an overview of the key findings and debates on the topic

Writing the literature review shows your reader how your work relates to existing research and what new insights it will contribute.

The literature review usually comes near the beginning of your  dissertation . After the introduction , it grounds your research in a scholarly field and leads directly to your theoretical framework or methodology .

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Literature Reviews

What this handout is about.

This handout will explain what literature reviews are and offer insights into the form and construction of literature reviews in the humanities, social sciences, and sciences.

Introduction

OK. You’ve got to write a literature review. You dust off a novel and a book of poetry, settle down in your chair, and get ready to issue a “thumbs up” or “thumbs down” as you leaf through the pages. “Literature review” done. Right?

Wrong! The “literature” of a literature review refers to any collection of materials on a topic, not necessarily the great literary texts of the world. “Literature” could be anything from a set of government pamphlets on British colonial methods in Africa to scholarly articles on the treatment of a torn ACL. And a review does not necessarily mean that your reader wants you to give your personal opinion on whether or not you liked these sources.

What is a literature review, then?

A literature review discusses published information in a particular subject area, and sometimes information in a particular subject area within a certain time period.

A literature review can be just a simple summary of the sources, but it usually has an organizational pattern and combines both summary and synthesis. A summary is a recap of the important information of the source, but a synthesis is a re-organization, or a reshuffling, of that information. It might give a new interpretation of old material or combine new with old interpretations. Or it might trace the intellectual progression of the field, including major debates. And depending on the situation, the literature review may evaluate the sources and advise the reader on the most pertinent or relevant.

But how is a literature review different from an academic research paper?

The main focus of an academic research paper is to develop a new argument, and a research paper is likely to contain a literature review as one of its parts. In a research paper, you use the literature as a foundation and as support for a new insight that you contribute. The focus of a literature review, however, is to summarize and synthesize the arguments and ideas of others without adding new contributions.

Why do we write literature reviews?

Literature reviews provide you with a handy guide to a particular topic. If you have limited time to conduct research, literature reviews can give you an overview or act as a stepping stone. For professionals, they are useful reports that keep them up to date with what is current in the field. For scholars, the depth and breadth of the literature review emphasizes the credibility of the writer in his or her field. Literature reviews also provide a solid background for a research paper’s investigation. Comprehensive knowledge of the literature of the field is essential to most research papers.

Who writes these things, anyway?

Literature reviews are written occasionally in the humanities, but mostly in the sciences and social sciences; in experiment and lab reports, they constitute a section of the paper. Sometimes a literature review is written as a paper in itself.

Let’s get to it! What should I do before writing the literature review?

If your assignment is not very specific, seek clarification from your instructor:

  • Roughly how many sources should you include?
  • What types of sources (books, journal articles, websites)?
  • Should you summarize, synthesize, or critique your sources by discussing a common theme or issue?
  • Should you evaluate your sources?
  • Should you provide subheadings and other background information, such as definitions and/or a history?

Find models

Look for other literature reviews in your area of interest or in the discipline and read them to get a sense of the types of themes you might want to look for in your own research or ways to organize your final review. You can simply put the word “review” in your search engine along with your other topic terms to find articles of this type on the Internet or in an electronic database. The bibliography or reference section of sources you’ve already read are also excellent entry points into your own research.

Narrow your topic

There are hundreds or even thousands of articles and books on most areas of study. The narrower your topic, the easier it will be to limit the number of sources you need to read in order to get a good survey of the material. Your instructor will probably not expect you to read everything that’s out there on the topic, but you’ll make your job easier if you first limit your scope.

Keep in mind that UNC Libraries have research guides and to databases relevant to many fields of study. You can reach out to the subject librarian for a consultation: https://library.unc.edu/support/consultations/ .

And don’t forget to tap into your professor’s (or other professors’) knowledge in the field. Ask your professor questions such as: “If you had to read only one book from the 90’s on topic X, what would it be?” Questions such as this help you to find and determine quickly the most seminal pieces in the field.

Consider whether your sources are current

Some disciplines require that you use information that is as current as possible. In the sciences, for instance, treatments for medical problems are constantly changing according to the latest studies. Information even two years old could be obsolete. However, if you are writing a review in the humanities, history, or social sciences, a survey of the history of the literature may be what is needed, because what is important is how perspectives have changed through the years or within a certain time period. Try sorting through some other current bibliographies or literature reviews in the field to get a sense of what your discipline expects. You can also use this method to consider what is currently of interest to scholars in this field and what is not.

Strategies for writing the literature review

Find a focus.

A literature review, like a term paper, is usually organized around ideas, not the sources themselves as an annotated bibliography would be organized. This means that you will not just simply list your sources and go into detail about each one of them, one at a time. No. As you read widely but selectively in your topic area, consider instead what themes or issues connect your sources together. Do they present one or different solutions? Is there an aspect of the field that is missing? How well do they present the material and do they portray it according to an appropriate theory? Do they reveal a trend in the field? A raging debate? Pick one of these themes to focus the organization of your review.

Convey it to your reader

A literature review may not have a traditional thesis statement (one that makes an argument), but you do need to tell readers what to expect. Try writing a simple statement that lets the reader know what is your main organizing principle. Here are a couple of examples:

The current trend in treatment for congestive heart failure combines surgery and medicine. More and more cultural studies scholars are accepting popular media as a subject worthy of academic consideration.

Consider organization

You’ve got a focus, and you’ve stated it clearly and directly. Now what is the most effective way of presenting the information? What are the most important topics, subtopics, etc., that your review needs to include? And in what order should you present them? Develop an organization for your review at both a global and local level:

First, cover the basic categories

Just like most academic papers, literature reviews also must contain at least three basic elements: an introduction or background information section; the body of the review containing the discussion of sources; and, finally, a conclusion and/or recommendations section to end the paper. The following provides a brief description of the content of each:

  • Introduction: Gives a quick idea of the topic of the literature review, such as the central theme or organizational pattern.
  • Body: Contains your discussion of sources and is organized either chronologically, thematically, or methodologically (see below for more information on each).
  • Conclusions/Recommendations: Discuss what you have drawn from reviewing literature so far. Where might the discussion proceed?

Organizing the body

Once you have the basic categories in place, then you must consider how you will present the sources themselves within the body of your paper. Create an organizational method to focus this section even further.

To help you come up with an overall organizational framework for your review, consider the following scenario:

You’ve decided to focus your literature review on materials dealing with sperm whales. This is because you’ve just finished reading Moby Dick, and you wonder if that whale’s portrayal is really real. You start with some articles about the physiology of sperm whales in biology journals written in the 1980’s. But these articles refer to some British biological studies performed on whales in the early 18th century. So you check those out. Then you look up a book written in 1968 with information on how sperm whales have been portrayed in other forms of art, such as in Alaskan poetry, in French painting, or on whale bone, as the whale hunters in the late 19th century used to do. This makes you wonder about American whaling methods during the time portrayed in Moby Dick, so you find some academic articles published in the last five years on how accurately Herman Melville portrayed the whaling scene in his novel.

Now consider some typical ways of organizing the sources into a review:

  • Chronological: If your review follows the chronological method, you could write about the materials above according to when they were published. For instance, first you would talk about the British biological studies of the 18th century, then about Moby Dick, published in 1851, then the book on sperm whales in other art (1968), and finally the biology articles (1980s) and the recent articles on American whaling of the 19th century. But there is relatively no continuity among subjects here. And notice that even though the sources on sperm whales in other art and on American whaling are written recently, they are about other subjects/objects that were created much earlier. Thus, the review loses its chronological focus.
  • By publication: Order your sources by publication chronology, then, only if the order demonstrates a more important trend. For instance, you could order a review of literature on biological studies of sperm whales if the progression revealed a change in dissection practices of the researchers who wrote and/or conducted the studies.
  • By trend: A better way to organize the above sources chronologically is to examine the sources under another trend, such as the history of whaling. Then your review would have subsections according to eras within this period. For instance, the review might examine whaling from pre-1600-1699, 1700-1799, and 1800-1899. Under this method, you would combine the recent studies on American whaling in the 19th century with Moby Dick itself in the 1800-1899 category, even though the authors wrote a century apart.
  • Thematic: Thematic reviews of literature are organized around a topic or issue, rather than the progression of time. However, progression of time may still be an important factor in a thematic review. For instance, the sperm whale review could focus on the development of the harpoon for whale hunting. While the study focuses on one topic, harpoon technology, it will still be organized chronologically. The only difference here between a “chronological” and a “thematic” approach is what is emphasized the most: the development of the harpoon or the harpoon technology.But more authentic thematic reviews tend to break away from chronological order. For instance, a thematic review of material on sperm whales might examine how they are portrayed as “evil” in cultural documents. The subsections might include how they are personified, how their proportions are exaggerated, and their behaviors misunderstood. A review organized in this manner would shift between time periods within each section according to the point made.
  • Methodological: A methodological approach differs from the two above in that the focusing factor usually does not have to do with the content of the material. Instead, it focuses on the “methods” of the researcher or writer. For the sperm whale project, one methodological approach would be to look at cultural differences between the portrayal of whales in American, British, and French art work. Or the review might focus on the economic impact of whaling on a community. A methodological scope will influence either the types of documents in the review or the way in which these documents are discussed. Once you’ve decided on the organizational method for the body of the review, the sections you need to include in the paper should be easy to figure out. They should arise out of your organizational strategy. In other words, a chronological review would have subsections for each vital time period. A thematic review would have subtopics based upon factors that relate to the theme or issue.

Sometimes, though, you might need to add additional sections that are necessary for your study, but do not fit in the organizational strategy of the body. What other sections you include in the body is up to you. Put in only what is necessary. Here are a few other sections you might want to consider:

  • Current Situation: Information necessary to understand the topic or focus of the literature review.
  • History: The chronological progression of the field, the literature, or an idea that is necessary to understand the literature review, if the body of the literature review is not already a chronology.
  • Methods and/or Standards: The criteria you used to select the sources in your literature review or the way in which you present your information. For instance, you might explain that your review includes only peer-reviewed articles and journals.

Questions for Further Research: What questions about the field has the review sparked? How will you further your research as a result of the review?

Begin composing

Once you’ve settled on a general pattern of organization, you’re ready to write each section. There are a few guidelines you should follow during the writing stage as well. Here is a sample paragraph from a literature review about sexism and language to illuminate the following discussion:

However, other studies have shown that even gender-neutral antecedents are more likely to produce masculine images than feminine ones (Gastil, 1990). Hamilton (1988) asked students to complete sentences that required them to fill in pronouns that agreed with gender-neutral antecedents such as “writer,” “pedestrian,” and “persons.” The students were asked to describe any image they had when writing the sentence. Hamilton found that people imagined 3.3 men to each woman in the masculine “generic” condition and 1.5 men per woman in the unbiased condition. Thus, while ambient sexism accounted for some of the masculine bias, sexist language amplified the effect. (Source: Erika Falk and Jordan Mills, “Why Sexist Language Affects Persuasion: The Role of Homophily, Intended Audience, and Offense,” Women and Language19:2).

Use evidence

In the example above, the writers refer to several other sources when making their point. A literature review in this sense is just like any other academic research paper. Your interpretation of the available sources must be backed up with evidence to show that what you are saying is valid.

Be selective

Select only the most important points in each source to highlight in the review. The type of information you choose to mention should relate directly to the review’s focus, whether it is thematic, methodological, or chronological.

Use quotes sparingly

Falk and Mills do not use any direct quotes. That is because the survey nature of the literature review does not allow for in-depth discussion or detailed quotes from the text. Some short quotes here and there are okay, though, if you want to emphasize a point, or if what the author said just cannot be rewritten in your own words. Notice that Falk and Mills do quote certain terms that were coined by the author, not common knowledge, or taken directly from the study. But if you find yourself wanting to put in more quotes, check with your instructor.

Summarize and synthesize

Remember to summarize and synthesize your sources within each paragraph as well as throughout the review. The authors here recapitulate important features of Hamilton’s study, but then synthesize it by rephrasing the study’s significance and relating it to their own work.

Keep your own voice

While the literature review presents others’ ideas, your voice (the writer’s) should remain front and center. Notice that Falk and Mills weave references to other sources into their own text, but they still maintain their own voice by starting and ending the paragraph with their own ideas and their own words. The sources support what Falk and Mills are saying.

Use caution when paraphrasing

When paraphrasing a source that is not your own, be sure to represent the author’s information or opinions accurately and in your own words. In the preceding example, Falk and Mills either directly refer in the text to the author of their source, such as Hamilton, or they provide ample notation in the text when the ideas they are mentioning are not their own, for example, Gastil’s. For more information, please see our handout on plagiarism .

Revise, revise, revise

Draft in hand? Now you’re ready to revise. Spending a lot of time revising is a wise idea, because your main objective is to present the material, not the argument. So check over your review again to make sure it follows the assignment and/or your outline. Then, just as you would for most other academic forms of writing, rewrite or rework the language of your review so that you’ve presented your information in the most concise manner possible. Be sure to use terminology familiar to your audience; get rid of unnecessary jargon or slang. Finally, double check that you’ve documented your sources and formatted the review appropriately for your discipline. For tips on the revising and editing process, see our handout on revising drafts .

Works consulted

We consulted these works while writing this handout. This is not a comprehensive list of resources on the handout’s topic, and we encourage you to do your own research to find additional publications. Please do not use this list as a model for the format of your own reference list, as it may not match the citation style you are using. For guidance on formatting citations, please see the UNC Libraries citation tutorial . We revise these tips periodically and welcome feedback.

Anson, Chris M., and Robert A. Schwegler. 2010. The Longman Handbook for Writers and Readers , 6th ed. New York: Longman.

Jones, Robert, Patrick Bizzaro, and Cynthia Selfe. 1997. The Harcourt Brace Guide to Writing in the Disciplines . New York: Harcourt Brace.

Lamb, Sandra E. 1998. How to Write It: A Complete Guide to Everything You’ll Ever Write . Berkeley: Ten Speed Press.

Rosen, Leonard J., and Laurence Behrens. 2003. The Allyn & Bacon Handbook , 5th ed. New York: Longman.

Troyka, Lynn Quittman, and Doug Hesse. 2016. Simon and Schuster Handbook for Writers , 11th ed. London: Pearson.

You may reproduce it for non-commercial use if you use the entire handout and attribute the source: The Writing Center, University of North Carolina at Chapel Hill

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Research Methods

  • Getting Started
  • Literature Review Research
  • Research Design
  • Research Design By Discipline
  • SAGE Research Methods
  • Teaching with SAGE Research Methods

Literature Review

  • What is a Literature Review?
  • What is NOT a Literature Review?
  • Purposes of a Literature Review
  • Types of Literature Reviews
  • Literature Reviews vs. Systematic Reviews
  • Systematic vs. Meta-Analysis

Literature Review  is a comprehensive survey of the works published in a particular field of study or line of research, usually over a specific period of time, in the form of an in-depth, critical bibliographic essay or annotated list in which attention is drawn to the most significant works.

Also, we can define a literature review as the collected body of scholarly works related to a topic:

  • Summarizes and analyzes previous research relevant to a topic
  • Includes scholarly books and articles published in academic journals
  • Can be an specific scholarly paper or a section in a research paper

The objective of a Literature Review is to find previous published scholarly works relevant to an specific topic

  • Help gather ideas or information
  • Keep up to date in current trends and findings
  • Help develop new questions

A literature review is important because it:

  • Explains the background of research on a topic.
  • Demonstrates why a topic is significant to a subject area.
  • Helps focus your own research questions or problems
  • Discovers relationships between research studies/ideas.
  • Suggests unexplored ideas or populations
  • Identifies major themes, concepts, and researchers on a topic.
  • Tests assumptions; may help counter preconceived ideas and remove unconscious bias.
  • Identifies critical gaps, points of disagreement, or potentially flawed methodology or theoretical approaches.
  • Indicates potential directions for future research.

All content in this section is from Literature Review Research from Old Dominion University 

Keep in mind the following, a literature review is NOT:

Not an essay 

Not an annotated bibliography  in which you summarize each article that you have reviewed.  A literature review goes beyond basic summarizing to focus on the critical analysis of the reviewed works and their relationship to your research question.

Not a research paper   where you select resources to support one side of an issue versus another.  A lit review should explain and consider all sides of an argument in order to avoid bias, and areas of agreement and disagreement should be highlighted.

A literature review serves several purposes. For example, it

  • provides thorough knowledge of previous studies; introduces seminal works.
  • helps focus one’s own research topic.
  • identifies a conceptual framework for one’s own research questions or problems; indicates potential directions for future research.
  • suggests previously unused or underused methodologies, designs, quantitative and qualitative strategies.
  • identifies gaps in previous studies; identifies flawed methodologies and/or theoretical approaches; avoids replication of mistakes.
  • helps the researcher avoid repetition of earlier research.
  • suggests unexplored populations.
  • determines whether past studies agree or disagree; identifies controversy in the literature.
  • tests assumptions; may help counter preconceived ideas and remove unconscious bias.

As Kennedy (2007) notes*, it is important to think of knowledge in a given field as consisting of three layers. First, there are the primary studies that researchers conduct and publish. Second are the reviews of those studies that summarize and offer new interpretations built from and often extending beyond the original studies. Third, there are the perceptions, conclusions, opinion, and interpretations that are shared informally that become part of the lore of field. In composing a literature review, it is important to note that it is often this third layer of knowledge that is cited as "true" even though it often has only a loose relationship to the primary studies and secondary literature reviews.

Given this, while literature reviews are designed to provide an overview and synthesis of pertinent sources you have explored, there are several approaches to how they can be done, depending upon the type of analysis underpinning your study. Listed below are definitions of types of literature reviews:

Argumentative Review      This form examines literature selectively in order to support or refute an argument, deeply imbedded assumption, or philosophical problem already established in the literature. The purpose is to develop a body of literature that establishes a contrarian viewpoint. Given the value-laden nature of some social science research [e.g., educational reform; immigration control], argumentative approaches to analyzing the literature can be a legitimate and important form of discourse. However, note that they can also introduce problems of bias when they are used to to make summary claims of the sort found in systematic reviews.

Integrative Review      Considered a form of research that reviews, critiques, and synthesizes representative literature on a topic in an integrated way such that new frameworks and perspectives on the topic are generated. The body of literature includes all studies that address related or identical hypotheses. A well-done integrative review meets the same standards as primary research in regard to clarity, rigor, and replication.

Historical Review      Few things rest in isolation from historical precedent. Historical reviews are focused on examining research throughout a period of time, often starting with the first time an issue, concept, theory, phenomena emerged in the literature, then tracing its evolution within the scholarship of a discipline. The purpose is to place research in a historical context to show familiarity with state-of-the-art developments and to identify the likely directions for future research.

Methodological Review      A review does not always focus on what someone said [content], but how they said it [method of analysis]. This approach provides a framework of understanding at different levels (i.e. those of theory, substantive fields, research approaches and data collection and analysis techniques), enables researchers to draw on a wide variety of knowledge ranging from the conceptual level to practical documents for use in fieldwork in the areas of ontological and epistemological consideration, quantitative and qualitative integration, sampling, interviewing, data collection and data analysis, and helps highlight many ethical issues which we should be aware of and consider as we go through our study.

Systematic Review      This form consists of an overview of existing evidence pertinent to a clearly formulated research question, which uses pre-specified and standardized methods to identify and critically appraise relevant research, and to collect, report, and analyse data from the studies that are included in the review. Typically it focuses on a very specific empirical question, often posed in a cause-and-effect form, such as "To what extent does A contribute to B?"

Theoretical Review      The purpose of this form is to concretely examine the corpus of theory that has accumulated in regard to an issue, concept, theory, phenomena. The theoretical literature review help establish what theories already exist, the relationships between them, to what degree the existing theories have been investigated, and to develop new hypotheses to be tested. Often this form is used to help establish a lack of appropriate theories or reveal that current theories are inadequate for explaining new or emerging research problems. The unit of analysis can focus on a theoretical concept or a whole theory or framework.

* Kennedy, Mary M. "Defining a Literature."  Educational Researcher  36 (April 2007): 139-147.

All content in this section is from The Literature Review created by Dr. Robert Larabee USC

Robinson, P. and Lowe, J. (2015),  Literature reviews vs systematic reviews.  Australian and New Zealand Journal of Public Health, 39: 103-103. doi: 10.1111/1753-6405.12393

what are the 3 main sources of literature review

What's in the name? The difference between a Systematic Review and a Literature Review, and why it matters . By Lynn Kysh from University of Southern California

what are the 3 main sources of literature review

Systematic review or meta-analysis?

A  systematic review  answers a defined research question by collecting and summarizing all empirical evidence that fits pre-specified eligibility criteria.

A  meta-analysis  is the use of statistical methods to summarize the results of these studies.

Systematic reviews, just like other research articles, can be of varying quality. They are a significant piece of work (the Centre for Reviews and Dissemination at York estimates that a team will take 9-24 months), and to be useful to other researchers and practitioners they should have:

  • clearly stated objectives with pre-defined eligibility criteria for studies
  • explicit, reproducible methodology
  • a systematic search that attempts to identify all studies
  • assessment of the validity of the findings of the included studies (e.g. risk of bias)
  • systematic presentation, and synthesis, of the characteristics and findings of the included studies

Not all systematic reviews contain meta-analysis. 

Meta-analysis is the use of statistical methods to summarize the results of independent studies. By combining information from all relevant studies, meta-analysis can provide more precise estimates of the effects of health care than those derived from the individual studies included within a review.  More information on meta-analyses can be found in  Cochrane Handbook, Chapter 9 .

A meta-analysis goes beyond critique and integration and conducts secondary statistical analysis on the outcomes of similar studies.  It is a systematic review that uses quantitative methods to synthesize and summarize the results.

An advantage of a meta-analysis is the ability to be completely objective in evaluating research findings.  Not all topics, however, have sufficient research evidence to allow a meta-analysis to be conducted.  In that case, an integrative review is an appropriate strategy. 

Some of the content in this section is from Systematic reviews and meta-analyses: step by step guide created by Kate McAllister.

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What is a Literature Review?

A literature or narrative review is a comprehensive review and analysis of the published literature on a specific topic or research question. The literature that is reviewed contains: books, articles, academic articles, conference proceedings, association papers, and dissertations. It contains the most pertinent studies and points to important past and current research and practices. It provides background and context, and shows how your research will contribute to the field. 

A literature review should: 

  • Provide a comprehensive and updated review of the literature;
  • Explain why this review has taken place;
  • Articulate a position or hypothesis;
  • Acknowledge and account for conflicting and corroborating points of view

From  S age Research Methods

Purpose of a Literature Review

A literature review can be written as an introduction to a study to:

  • Demonstrate how a study fills a gap in research
  • Compare a study with other research that's been done

Or it can be a separate work (a research article on its own) which:

  • Organizes or describes a topic
  • Describes variables within a particular issue/problem

Limitations of a Literature Review

Some of the limitations of a literature review are:

  • It's a snapshot in time. Unlike other reviews, this one has beginning, a middle and an end. There may be future developments that could make your work less relevant.
  • It may be too focused. Some niche studies may miss the bigger picture.
  • It can be difficult to be comprehensive. There is no way to make sure all the literature on a topic was considered.
  • It is easy to be biased if you stick to top tier journals. There may be other places where people are publishing exemplary research. Look to open access publications and conferences to reflect a more inclusive collection. Also, make sure to include opposing views (and not just supporting evidence).

Source: Grant, Maria J., and Andrew Booth. “A Typology of Reviews: An Analysis of 14 Review Types and Associated Methodologies.” Health Information & Libraries Journal, vol. 26, no. 2, June 2009, pp. 91–108. Wiley Online Library, doi:10.1111/j.1471-1842.2009.00848.x.

Meryl Brodsky : Communication and Information Studies

Hannah Chapman Tripp : Biology, Neuroscience

Carolyn Cunningham : Human Development & Family Sciences, Psychology, Sociology

Larayne Dallas : Engineering

Janelle Hedstrom : Special Education, Curriculum & Instruction, Ed Leadership & Policy ​

Susan Macicak : Linguistics

Imelda Vetter : Dell Medical School

For help in other subject areas, please see the guide to library specialists by subject .

Periodically, UT Libraries runs a workshop covering the basics and library support for literature reviews. While we try to offer these once per academic year, we find providing the recording to be helpful to community members who have missed the session. Following is the most recent recording of the workshop, Conducting a Literature Review. To view the recording, a UT login is required.

  • October 26, 2022 recording
  • Last Updated: Oct 26, 2022 2:49 PM
  • URL: https://guides.lib.utexas.edu/literaturereviews

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Literature Review: Lit Review Sources

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Where do I find information for a literature review?

Research is done by...

...by way of...

...communicated through...

...and organized in...

Types of sources for a review...

  • Primary source: Usually a report by the original researchers of a study (unfiltered sources)
  • Secondary source: Description or summary by somebody other than the original researcher, e.g. a review article (filtered sources)
  • Conceptual/theoretical: Papers concerned with description or analysis of theories or concepts associated with the topic
  • Anecdotal/opinion/clinical: Views or opinions about the subject that are not research, review or theoretical (case studies or reports from clinical settings)

A Heirarchy of research information:

Source: SUNY Downstate Medical Center. Medical Research Library of Brooklyn. Evidence Based Medicine Course. A Guide to Research Methods: The Evidence Pyramid: http://library.downstate.edu/EBM2/2100.htm

Life Cycle of Publication

Click image to enlarge

Publication Cycle of Scientific Literature

Scientific information has a ‘life cycle’ of its own… it is born as an idea, and then matures and becomes more available to the public. First it appears within the so-called ‘invisible college’ of experts in the field, discussed at conferences and symposia or posted as pre-prints for comments and corrections. Then it appears in the published literature (the primary literature), often as a journal article in a peer-reviewed journal.

Researchers can use the indexing and alerting services of the secondary literature to find out what has been published in a field. Depending on how much information is added by the indexer or abstracter, this may take a few months (though electronic publication has sped up this process). Finally, the information may appear in more popular or reference sources, sometimes called the tertiary literature.

The person beginning a literature search may take this process in reverse: using tertiary sources for general background, then going to the secondary literature to survey what has been published, following up by finding the original (primary) sources, and generating their own research Idea.

(Original content by Wade Lee-Smith)

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What is a literature review?

A literature review is an integrated analysis -- not just a summary-- of scholarly writings and other relevant evidence related directly to your research question.  That is, it represents a synthesis of the evidence that provides background information on your topic and shows a association between the evidence and your research question.

A literature review may be a stand alone work or the introduction to a larger research paper, depending on the assignment.  Rely heavily on the guidelines your instructor has given you.

Why is it important?

A literature review is important because it:

  • Explains the background of research on a topic.
  • Demonstrates why a topic is significant to a subject area.
  • Discovers relationships between research studies/ideas.
  • Identifies major themes, concepts, and researchers on a topic.
  • Identifies critical gaps and points of disagreement.
  • Discusses further research questions that logically come out of the previous studies.

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APA Style Blog - for those harder to find answers

1. Choose a topic. Define your research question.

Your literature review should be guided by your central research question.  The literature represents background and research developments related to a specific research question, interpreted and analyzed by you in a synthesized way.

  • Make sure your research question is not too broad or too narrow.  Is it manageable?
  • Begin writing down terms that are related to your question. These will be useful for searches later.
  • If you have the opportunity, discuss your topic with your professor and your class mates.

2. Decide on the scope of your review

How many studies do you need to look at? How comprehensive should it be? How many years should it cover? 

  • This may depend on your assignment.  How many sources does the assignment require?

3. Select the databases you will use to conduct your searches.

Make a list of the databases you will search. 

Where to find databases:

  • use the tabs on this guide
  • Find other databases in the Nursing Information Resources web page
  • More on the Medical Library web page
  • ... and more on the Yale University Library web page

4. Conduct your searches to find the evidence. Keep track of your searches.

  • Use the key words in your question, as well as synonyms for those words, as terms in your search. Use the database tutorials for help.
  • Save the searches in the databases. This saves time when you want to redo, or modify, the searches. It is also helpful to use as a guide is the searches are not finding any useful results.
  • Review the abstracts of research studies carefully. This will save you time.
  • Use the bibliographies and references of research studies you find to locate others.
  • Check with your professor, or a subject expert in the field, if you are missing any key works in the field.
  • Ask your librarian for help at any time.
  • Use a citation manager, such as EndNote as the repository for your citations. See the EndNote tutorials for help.

Review the literature

Some questions to help you analyze the research:

  • What was the research question of the study you are reviewing? What were the authors trying to discover?
  • Was the research funded by a source that could influence the findings?
  • What were the research methodologies? Analyze its literature review, the samples and variables used, the results, and the conclusions.
  • Does the research seem to be complete? Could it have been conducted more soundly? What further questions does it raise?
  • If there are conflicting studies, why do you think that is?
  • How are the authors viewed in the field? Has this study been cited? If so, how has it been analyzed?

Tips: 

  • Review the abstracts carefully.  
  • Keep careful notes so that you may track your thought processes during the research process.
  • Create a matrix of the studies for easy analysis, and synthesis, across all of the studies.
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What Is a Literature Review?

Review the literature, write the literature review, further reading, learning objectives, attribution.

This guide is designed to:

  • Identify the sections and purpose of a literature review in academic writing
  • Review practical strategies and organizational methods for preparing a literature review

A literature review is a summary and synthesis of scholarly research on a specific topic. It should answer questions such as:

  • What research has been done on the topic?
  • Who are the key researchers and experts in the field?
  • What are the common theories and methodologies?
  • Are there challenges, controversies, and contradictions?
  • Are there gaps in the research that your approach addresses?

The process of reviewing existing research allows you to fine-tune your research question and contextualize your own work. Preparing a literature review is a cyclical process. You may find that the research question you begin with evolves as you learn more about the topic.

Once you have defined your research question , focus on learning what other scholars have written on the topic.

In order to  do a thorough search of the literature  on the topic, define the basic criteria:

  • Databases and journals: Look at the  subject guide  related to your topic for recommended databases. Review the  tutorial on finding articles  for tips. 
  • Books: Search BruKnow, the Library's catalog. Steps to searching ebooks are covered in the  Finding Ebooks tutorial .
  • What time period should it cover? Is currency important?
  • Do I know of primary and secondary sources that I can use as a way to find other information?
  • What should I be aware of when looking at popular, trade, and scholarly resources ? 

One strategy is to review bibliographies for sources that relate to your interest. For more on this technique, look at the tutorial on finding articles when you have a citation .

Tip: Use a Synthesis Matrix

As you read sources, themes will emerge that will help you to organize the review. You can use a simple Synthesis Matrix to track your notes as you read. From this work, a concept map emerges that provides an overview of the literature and ways in which it connects. Working with Zotero to capture the citations, you build the structure for writing your literature review.

How do I know when I am done?

A key indicator for knowing when you are done is running into the same articles and materials. With no new information being uncovered, you are likely exhausting your current search and should modify search terms or search different catalogs or databases. It is also possible that you have reached a point when you can start writing the literature review.

Tip: Manage Your Citations

These citation management tools also create citations, footnotes, and bibliographies with just a few clicks:

Zotero Tutorial

Endnote Tutorial

Your literature review should be focused on the topic defined in your research question. It should be written in a logical, structured way and maintain an objective perspective and use a formal voice.

Review the Summary Table you created for themes and connecting ideas. Use the following guidelines to prepare an outline of the main points you want to make. 

  • Synthesize previous research on the topic.
  • Aim to include both summary and synthesis.
  • Include literature that supports your research question as well as that which offers a different perspective.
  • Avoid relying on one author or publication too heavily.
  • Select an organizational structure, such as chronological, methodological, and thematic.

The three elements of a literature review are introduction, body, and conclusion.

Introduction

  • Define the topic of the literature review, including any terminology.
  • Introduce the central theme and organization of the literature review.
  • Summarize the state of research on the topic.
  • Frame the literature review with your research question.
  • Focus on ways to have the body of literature tell its own story. Do not add your own interpretations at this point.
  • Look for patterns and find ways to tie the pieces together.
  • Summarize instead of quote.
  • Weave the points together rather than list summaries of each source.
  • Include the most important sources, not everything you have read.
  • Summarize the review of the literature.
  • Identify areas of further research on the topic.
  • Connect the review with your research.
  • DeCarlo, M. (2018). 4.1 What is a literature review? In Scientific Inquiry in Social Work. Open Social Work Education. https://scientificinquiryinsocialwork.pressbooks.com/chapter/4-1-what-is-a-literature-review/
  • Literature Reviews (n.d.) https://writingcenter.unc.edu/tips-and-tools/literature-reviews/ Accessed Nov. 10, 2021

This guide was designed to: 

  • Identify the sections and purpose of a literature review in academic writing 
  • Review practical strategies and organizational methods for preparing a literature review​

Content on this page adapted from: 

Frederiksen, L. and Phelps, S. (2017).   Literature Reviews for Education and Nursing Graduate Students.  Licensed CC BY 4.0

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Literature Review: The What, Why and How-to Guide — Strategies to Find Sources

  • Getting Started
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The Research Process

Interative Litearture Review Research Process image (Planning, Searching, Organizing, Analyzing and Writing [repeat at necessary]

Planning : Before searching for articles or books, brainstorm to develop keywords that better describe your research question.

Searching : While searching, take note of what other keywords are used to describe your topic, and use them to conduct additional searches

     ♠ Most articles include a keyword section

     ♠ Key concepts may change names throughout time so make sure to check for variations

Organizing : Start organizing your results by categories/key concepts or any organizing principle that make sense for you . This will help you later when you are ready to analyze your findings

Analyzing : While reading, start making notes of key concepts and commonalities and disagreement among the research articles you find.

♠ Create a spreadsheet  to record what articles you are finding useful and why.

♠ Create fields to write summaries of articles or quotes for future citing and paraphrasing .

Writing : Synthesize your findings. Use your own voice to explain to your readers what you learned about the literature on your topic. What are its weaknesses and strengths? What is missing or ignored?

Repeat : At any given time of the process, you can go back to a previous step as necessary.

Advanced Searching

All databases have Help pages that explain the best way to search their product. When doing literature reviews, you will want to take advantage of these features since they can facilitate not only finding the articles that you really need but also controlling the number of results and how relevant they are for your search. The most common features available in the advanced search option of databases and library online catalogs are:

  • Boolean Searching (AND, OR, NOT): Allows you to connect search terms in a way that can either limit or expand your search results 
  • Proximity Searching (N/# or W/#): Allows you to search for two or more words that occur within a specified number of words (or fewer) of each other in the database
  • Limiters/Filters : These are options that let you control what type of document you want to search: article type, date, language, publication, etc.
  • Question mark (?) or a pound sign (#) for wildcard: Used for retrieving alternate spellings of a word: colo?r will retrieve both the American spelling "color" as well as the British spelling "colour." 
  • Asterisk (*) for truncation: Used for retrieving multiple forms of a word: comput* retrieves computer, computers, computing, etc.

Want to keep track of updates to your searches? Create an account in the database to receive an alert when a new article is published that meets your search parameters!

  • EBSCOhost Advanced Search Tutorial Tips for searching a platform that hosts many library databases
  • Library's General Search Tips Check the Search tips to better used our library catalog and articles search system
  • ProQuest Database Search Tips Tips for searching another platform that hosts library databases

There is no magic number regarding how many sources you are going to need for your literature review; it all depends on the topic and what type of the literature review you are doing:

► Are you working on an emerging topic? You are not likely to find many sources, which is good because you are trying to prove that this is a topic that needs more research. But, it is not enough to say that you found few or no articles on your topic in your field. You need to look broadly to other disciplines (also known as triangulation ) to see if your research topic has been studied from other perspectives as a way to validate the uniqueness of your research question.

► Are you working on something that has been studied extensively? Then you are going to find many sources and you will want to limit how far back you want to look. Use limiters to eliminate research that may be dated and opt to search for resources published within the last 5-10 years.

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Researching for your literature review: Literature sources

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Scholarly databases

It's important to make a considered decision as to where to search for your review of the literature. It's uncommon for a disciplinary area to be covered by a single publisher, so searching a single publisher platform or database is unlikely to give you sufficient coverage of studies for a review. A good quality literature review involves searching a number of databases individually.

The most common method is to search a combination of large inter-disciplinary databases such as Scopus & Web of Science Core Collection, and some subject-specific databases (such as PsycInfo or EconLit etc.). The Library databases are an excellent place to start for sources of peer-reviewed journal articles.

Depending on disciplinary expectations, or the topic of our review, you may also need to consider sources or search methods other than database searching. There is general information below on searching grey literature. However, due to the wide varieties of grey literature available, you may need to spend some time investigating sources relevant for your specific need.

Grey literature

Grey literature is information which has been published informally or non-commercially (where the main purpose of the producing body is not commercial publishing) or remains unpublished. One example may be Government publications.

Grey literature may be included in a literature review to minimise publication bias . The quality of grey literature can vary greatly - some may be peer reviewed whereas some may not have been through a traditional editorial process.

See the Grey Literature guide for further information on finding and evaluating grey sources.

See the Moodle book MNHS: Systematically searching the grey literature for a comprehensive module on grey literature for systematic reviews.

In certain disciplines (such as physics) there can be a culture of preprints being made available prior to submissions to journals. There has also been a noticeable rise in preprints in medical and health areas in the wake of Covid-19.

If preprints are relevant for you, you can search preprint servers directly. A workaround might be to utilise a search engine such as Google Scholar to search specifically for preprints, as Google Scholar has timely coverage of most preprint servers including ArXiv, RePec, SSRN, BioRxiv, and MedRxiv.

Articles in Press are not preprints, but are accepted manuscripts that are not yet formally published. Articles in Press have been made available as an early access online version of a paper that may not yet have received its final formatting or an allocation of a volume/issue number. As well as being available on a journal's website, Articles in Press are available in databases such as Scopus and Web of Science, and so (unlike preprints) don't necessarily require a separate search.

Conference papers

Conference papers are typically published in conference proceedings (the collection of papers presented at a conference), and may be found on an organisation or Society's website, as a journal, or as a special issue of journal.

In certain disciplines (such as computer science), conference papers may be highly regarded as a form of scholarly communication; the conferences are highly selective, the papers are generally peer reviewed, and papers are published in proceedings affiliated with high-quality publishing houses.

Conference papers may be indexed in a range of scholarly databases. If you only want to see conference papers, database limits can be used to filter results, or try a specific index such as the examples below:

  • Conference proceedings citation index. Social science & humanities (CPCI-SSH)
  • Conference proceedings citation index. Science (CPCI-S)
  • ASME digital library conference proceedings

Honours students and postgraduates may request conference papers through Interlibrary Loans . However, conference paper requests may take longer than traditional article requests as they can be difficult to locate; they may have been only supplied to attendees or not formally published. Sometimes only the abstract is available.

If you are specifically looking for statistical data, try searching for the keyword statistics in a Google Advanced Search and limiting by a relevant site or domain. Below are some examples of sites, or you can try a domain such as .gov for government websites.

Statistical data can be found in the following selected sources:

  • Australian Bureau of Statistics
  • World Health Organization: Health Data and statistics
  • Higher Education Statistics
  • UNESCO Institute for Statistics
  • Tourism Australia Statistics

For a list of databases that include statistics see: Databases by Subject: Statistics .

If you are specifically looking for information found in newspapers, the library has a large collection of Australian and overseas newspapers, both current and historical.

To search the full-text of newspapers in electronic format use a database such as  Newsbank.

Alternatively, see the Newspapers subject guide for comprehensive information on newspaper sources available via Monash University library and open source databases, as well as searching tips, online videos and more.

Dissertations and theses

The Monash University Library Theses subject guide provides resources and guidelines for locating and accessing theses (dissertations) produced by Monash University as well as other universities in Australia and internationally.  

International theses:

There are a number of theses databases and repositories.

A popular source is:

  • ProQuest Dissertations & Theses Global  which predominantly, covers North American masters and doctoral theses. Full text is available for theses added since 1997. 

Australia and New Zealand theses:

Theses that are available in the library can be found using the  Search catalogue.

These include:

  • Monash doctoral, masters and a small number of honours theses 
  • other Australian and overseas theses that have been purchased for the collection.

Formats include print (not available for loan), microfiche and online (some may have access restrictions).

Trove includes doctoral, masters and some honours theses from all Australian and New Zealand universities, as well as theses awarded elsewhere but held by Australian institutions.

Tips:  

  • Type in the title, author surname and/or keywords. Then on the results page refine your search to 'thesis'.
  • Alternatively, use the Advanced search and include 'thesis' as a keyword or limi t your result to format = thesis
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  • Back to Research Help

The Literature Review

  • What is a Literature Review?
  • Plan Your Literature Review
  • Identify a Research Gap
  • Define Your Research Question
  • Search the Literature
  • Analyze Your Research Results
  • Manage Research Results
  • Write the Literature Review

what are the 3 main sources of literature review

What is a Literature Review?  What is its purpose?

The purpose of a literature review is to offer a  comprehensive review of scholarly literature on a specific topic along with an  evaluation of the strengths and weaknesses of authors' arguments . In other words, you are summarizing research available on a certain topic and then drawing conclusions about researchers' findings. To make gathering research easier, be sure to start with a narrow/specific topic and then widen your topic if necessary.

A thorough literature review provides an accurate description of current knowledge on a topic and identifies areas for future research.  Are there gaps or areas that require further study and exploration? What opportunities are there for further research? What is missing from my collection of resources? Are more resources needed?

It is important to note that conclusions described in the literature you gather may contradict each other completely or in part.  Recognize that knowledge creation is collective and cumulative.  Current research is built upon past research findings and discoveries.  Research may bring previously accepted conclusions into question.  A literature review presents current knowledge on a topic and may point out various academic arguments within the discipline.

What a Literature Review is not

  • A literature review is not an annotated bibliography .  An annotated bibliography provides a brief summary, analysis, and reflection of resources included in the bibliography.  Often it is not a systematic review of existing research on a specific subject.  That said, creating an annotated bibliography throughout your research process may be helpful in managing the resources discovered through your research.
  • A literature review is not a research paper .  A research paper explores a topic and uses resources discovered through the research process to support a position on the topic.  In other words, research papers present one side of an issue.  A literature review explores all sides of the research topic and evaluates all positions and conclusions achieved through the scientific research process even though some conclusions may conflict partially or completely.

From the Online Library

Cover Art

SAGE Research Methods is a web-based research methods tool that covers quantitative, qualitative and mixed methods. Researchers can explore methods and concepts to help design research projects, understand a particular method or identify a new method, and write up research. Sage Research Methods focuses on methodology rather than disciplines, and is of potential use to researchers from the social sciences, health sciences and other research areas.

  • Sage Research Methods Project Planner - Reviewing the Literature View the resources and videos for a step-by-step guide to performing a literature review.

The Literature Review: Step by Step

Follow this step-by-step process by using the related tabs in this Guide.

  • Define your Research question
  • Analyze the material you’ve found
  • Manage the results of your research
  • Write your Review

Getting Started

Consider the following questions as you develop your research topic, conduct your research, and begin evaluating the resources discovered in the research process:

  • What is known about the subject?
  • Are there any gaps in the knowledge of the subject?
  • Have areas of further study been identified by other researchers that you may want to consider?
  • Who are the significant research personalities in this area?
  • Is there consensus about the topic?
  • What aspects have generated significant debate on the topic?
  • What methods or problems were identified by others studying in the field and how might they impact your research?
  • What is the most productive methodology for your research based on the literature you have reviewed?
  • What is the current status of research in this area?
  • What sources of information or data were identified that might be useful to you?
  • How detailed? Will it be a review of ALL relevant material or will the scope be limited to more recent material, e.g., the last five years.
  • Are you focusing on methodological approaches; on theoretical issues; on qualitative or quantitative research?

What is Academic Literature?

What is the difference between popular and scholarly literature?

To better understand the differences between popular and scholarly articles, comparing characteristics and purpose of the publications where these articles appear is helpful.

Popular Article (Magazine)

  • Articles are shorter and are written for the general public
  • General interest topics or current events are covered
  • Language is simple and easy to understand
  • Source material is not cited
  • Articles often include glossy photographs, graphics, or visuals
  • Articles are written by the publication's staff of journalists
  • Articles are edited and information is fact checked

Examples of magazines that contain popular articles:

what are the 3 main sources of literature review

Scholarly Article (Academic Journal)

  • Articles are written by scholars and researchers for academics, professionals, and experts in the field
  • Articles are longer and report original research findings
  • Topics are narrower in focus and provide in-depth analysis
  • Technical or scholarly language is used
  • Source material is cited
  • Charts and graphs illustrating research findings are included
  • Many are  "peer reviewed"  meaning that panels of experts review articles submitted for publication to ensure that proper research methods were used and research findings are contributing something new to the field before selecting for publication.

Examples of academic journals that contain scholarly articles:

what are the 3 main sources of literature review

Define your research question

Selecting a research topic can be overwhelming.  Consider following these steps:

1.  Brainstorm  research topic ideas

      - Free write: Set a timer for five minutes and write down as many ideas as you can in the allotted time

      -  Mind-Map  to explore how ideas are related

2.  Prioritize  topics based on personal interest and curiosity

3.  Pre-research

      - Explore encyclopedias and reference books for background information on the topic

      - Perform a quick database or Google search on the topic to explore current issues. 

4.  Focus the topic  by evaluating how much information is available on the topic

         - Too much information?  Consider narrowing the topic by focusing on a specific issue 

         - Too little information?  Consider broadening the topic 

5.  Determine your purpose  by considering whether your research is attempting to:

         - further the research on this topic

         - fill a gap in the research

         - support existing knowledge with new evidence

         - take a new approach or direction

         - question or challenge existing knowledge

6.  Finalize your research question

NOTE:  Be aware that your initial research question may change as you conduct research on your topic.

Searching the Literature

Research on your topic should be conducted in the academic literature.  The  Rasmussen University Online Library contains subject-focused databases that contain the leading academic journals in your programmatic area.

Consult the  Using the Online Library video tutorials  for information about how to effectively search library databases.

Watch the video below for tips on how to create a search statement that will provide relevant results

Need help starting your research?  Make a  research appointment with a Rasmussen Librarian .

what are the 3 main sources of literature review

TIP:  Document as you research.  Begin building your references list using the citation managers in one of these resources:

  • APA Academic Writer

Recommended programmatic databases include:

Data Science

Coverage includes computer engineering, computer theory & systems, research and development, and the social and professional implications of new technologies. Articles come from more than 1,900 academic journals, trade magazines, and professional publications.

Provides access to full-text peer-reviewed journals, transactions, magazines, conference proceedings, and published standards in the areas of electrical engineering, computer science, and electronics. It also provides access to the IEEE Standards Dictionary Online. Full-text available.

Computing, telecommunications, art, science and design databases from ProQuest.

Healthcare Management

Articles from scholarly business journals back as far as 1886 with content from all disciplines of business, including marketing, management, accounting, management information systems, production and operations management, finance, and economics. Contains 55 videos from the Harvard Faculty Seminar Series, on topics such as leadership, sustaining competitive advantage, and globalization. To access the videos, click "More" in the blue bar at the top. Select "Images/ Business Videos." Uncheck "Image Quick View Collection" to indicate you only wish to search for videos. Enter search terms.

Provides a truly comprehensive business research collection. The collection consists of the following databases and more: ABI/INFORM Complete, ProQuest Entrepreneurship, ProQuest Accounting & Tax, International Bibliography of Social Sciences (IBSS), ProQuest Asian Business and Reference, and Banking Information Source.

The definitive research tool for all areas of nursing and allied health literature. Geared towards the needs of nurses and medical professionals. Covers more than 750 journals from 1937 to present.

HPRC provides information on the creation, implementation and study of health care policy and the health care system. Topics covered include health care administration, economics, planning, law, quality control, ethics, and more.

PolicyMap is an online mapping site that provides data on demographics, real estate, health, jobs, and other areas across the U.S. Access and visualize data from Census and third-party records.

Human Resources

Articles from all subject areas gathered from more than 11,000 magazines, journals, books and reports. Subjects include astronomy, multicultural studies, humanities, geography, history, law, pharmaceutical sciences, women's studies, and more. Coverage from 1887 to present. Start your research here.

Cochrane gathers and summarizes the best evidence from research to help you make informed choices about treatments. Whether a doctor or nurse, patient, researcher or student, Cochrane evidence provides a tool to enhance your healthcare knowledge and decision making on topics ranging from allergies, blood disorders, and cancer, to mental health, pregnancy, urology, and wounds.

Health sciences, biology, science, and pharmaceutical information from ProQuest. Includes articles from scholarly, peer-reviewed journals, practical and professional development content from professional journals, and general interest articles from magazines and newspapers.

Joanna Briggs Institute Academic Collection contains evidence-based information from across the globe, including evidence summaries, systematic reviews, best practice guidelines, and more. Subjects include medical, nursing, and healthcare specialties.

Comprehensive source of full-text articles from more than 1,450 scholarly medical journals.

Articles from more than 35 nursing journals in full text, searchable as far back as 1995.

Analyzing Your Research Results

You have completed your research and discovered many, many academic articles on your topic.  The next step involves evaluating and organizing the literature found in the research process.

As you review, keep in mind that there are three types of research studies:

  • Quantitative
  • Qualitative 
  • Mixed Methods

Consider these questions as you review the articles you have gathered through the research process:

1. Does the study relate to your topic?

2. Were sound research methods used in conducting the study?

3. Does the research design fit the research question? What variables were chosen? Was the sample size adequate?

4. What conclusions were drawn?  Do the authors point out areas for further research?

Reading Academic Literature

Academic journals publish the results of research studies performed by experts in an academic discipline.  Articles selected for publication go through a rigorous peer-review process.  This process includes a thorough evaluation of the research submitted for publication by journal editors and other experts or peers in the field.  Editors select articles based on specific criteria including the research methods used, whether the research contributes new findings to the field of study, and how the research fits within the scope of the academic journal.  Articles selected often go through a revision process prior to publication.

Most academic journal articles include the following sections:

  • Abstract    (An executive summary of the study)
  • Introduction  (Definition of the research question to be studied)
  • Literature Review  (A summary of past research noting where gaps exist)
  • Methods  (The research design including variables, sample size, measurements)
  • Data   (Information gathered through the study often displayed in tables and charts)
  • Results   (Conclusions reached at the end of the study)
  • Conclusion   (Discussion of whether the study proved the thesis; may suggest opportunities for further research)
  • Bibliography  (A list of works cited in the journal article)

TIP:  To begin selecting articles for your research, read the   highlighted sections   to determine whether the academic journal article includes information relevant to your research topic.

Step 1: Skim the article

When sorting through multiple articles discovered in the research process, skimming through these sections of the article will help you determine whether the article will be useful in your research.

1.  Article title   and subject headings assigned to the article

2.   Abstract

3.   Introduction

4.  Conclusion

If the article fits your information need, go back and  read the article thoroughly.

TIP:  Create a folder on your computer to save copies of articles you plan to use in your thesis or research project.  Use  NoodleTools  or  APA Academic Writer  to save APA references.

Step 2: Determine Your Purpose

Think about how you will evaluate the academic articles you find and how you will determine whether to include them in your research project.  Ask yourself the following questions to focus your search in the academic literature:

  • ​Are you looking for an overview of a topic? an explanation of a specific concept, idea, or position?
  • Are you exploring gaps in the research to identify a new area for academic study?
  • Are you looking for research that supports or disagrees with your thesis or research question?
  • Are you looking for examples of a research design and/or research methods you are considering for your own research project?

Step 3: Read Critically

Before reading the article, ask yourself the following:

  • What is my research question?  What position am I trying to support?
  • What do I already know about this topic?  What do I need to learn?
  • How will I evaluate the article?  Author's reputation? Research design? Treatment of topic? 
  • What are my biases about the topic?

As you read the article make note of the following:

  • Who is the intended audience for this article?
  • What is the author's purpose in writing this article?
  • What is the main point?
  • How was the main point proven or supported?  
  • Were scientific methods used in conducting the research?
  • Do you agree or disagree with the author? Why?
  • How does this article compare or connect with other articles on the topic?
  • Does the author recommend areas for further study?
  • How does this article help to answer your research question?

Managing your Research

Tip:  Create APA references for resources as you discover them in the research process

Use APA Academic Writer or NoodleTools to generate citations and manage your resources.  Find information on how to use these resources in the Citation Tools Guide .

what are the 3 main sources of literature review

Writing the Literature Review

Once research has been completed, it is time to structure the literature review and begin summarizing and synthesizing information.  The following steps may help with this process:

  • Chronological
  • By research method used
  • Explore contradictory or conflicting conclusions
  • Read each study critically
  • Critique methodology, processes, and conclusions
  • Consider how the study relates to your topic

Writing Lab

  • Description of public health nursing nutrition assessment and interventions for home‐visited women. This article provides a nice review of the literature in the article introduction. You can see how the authors have used the existing literature to make a case for their research questions. more... less... Horning, M. L., Olsen, J. M., Lell, S., Thorson, D. R., & Monsen, K. A. (2018). Description of public health nursing nutrition assessment and interventions for home‐visited women. Public Health Nursing, 35(4), 317–326. https://doi.org/10.1111/phn.12410
  • Improving Diabetes Self-Efficacy in the Hispanic Population Through Self-Management Education Doctoral papers are a good place to see how literature reviews can be done. You can learn where they searched, what search terms they used, and how they decided which articles were included. Notice how the literature review is organized around the three main themes that came out of the literature search. more... less... Robles, A. N. (2023). Improving diabetes self-efficacy in the hispanic population through self-management education (Order No. 30635901). Available from ProQuest Dissertations & Theses Global: The Sciences and Engineering Collection. https://www.proquest.com/dissertations-theses/improving-diabetes-self-efficacy-hispanic/docview/2853708553/se-2
  • Exploring mediating effects between nursing leadership and patient safety from a person-centred perspective: A literature review Reading articles that publish the results of a systematic literature review is a great way to see in detail how a literature review is conducted. These articles provide an article matrix, which provides you an example of how you can document information about the articles you find in your own search. To see more examples, include "literature review" or "systematic review" as a search term. more... less... Wang, M., & Dewing, J. (2021). Exploring mediating effects between nursing leadership and patient safety from a person‐centred perspective: A literature review. Journal of Nursing Management, 29(5), 878–889. https://doi.org/10.1111/jonm.13226

Database Search Tips

  • Boolean Operators
  • Keywords vs. Subjects
  • Creating a Search String
  • Library databases are collections of resources that are searchable, including full-text articles, books, and encyclopedias.
  • Searching library databases is different than searching Google. Best results are achieved when using Keywords linked with Boolean Operators . 
  • Applying Limiters such as full-text, publication date, resource type, language, geographic location, and subject help to refine search results.
  • Utilizing Phrases or Fields , in addition to an awareness of Stop Words , can focus your search and retrieve more useful results.
  • Have questions? Ask a Librarian

Boolean Operators connect keywords or concepts logically to retrieve relevant articles, books, and other resources.  There are three Boolean Operators:

Using AND 

  • Narrows search results
  • Connects two or more keywords/concepts
  • All keywords/concepts connected with "and" must be in an article or resource to appear in the search results list

what are the 3 main sources of literature review

Venn diagram of the AND connector

Example: The result list will include resources that include both keywords -- "distracted driving" and "texting" -- in the same article or resource, represented in the shaded area where the circles intersect (area shaded in purple).

  • Broadens search results ("OR means more!")
  • Connects two or more synonyms or related keywords/concepts
  • Resources appearing in the results list will include any of the terms connected with the OR connector

what are the 3 main sources of literature review

Venn diagram of the OR connector

Example:  The result list will include resources that include the keyword "texting" OR the keyword "cell phone" (entire area shaded in blue); either is acceptable.

  • Excludes keywords or concepts from the search
  • Narrows results by removing resources that contain the keyword or term connected with the NOT connector
  • Use sparingly

what are the 3 main sources of literature review

Venn diagram of the NOT connector

Example: The result list will include all resources that include the term "car" (green area) but will exclude any resource that includes the term "motorcycle" (purple area) even though the term car may be present in the resource.

A library database searches for keywords throughout the entire resource record including the full-text of the resource, subject headings, tags, bibliographic information, etc.

  • Natural language words or short phrases that describe a concept or idea
  • Can retrieve too few or irrelevant results due to full-text searching (What words would an author use to write about this topic?)
  • Provide flexibility in a search
  • Must consider synonyms or related terms to improve search results
  • TIP: Build a Keyword List

what are the 3 main sources of literature review

Example:  The keyword list above was developed to find resources that discuss how texting while driving results in accidents.  Notice that there are synonyms (texting and "text messaging"), related terms ("cell phones" and texting), and spelling variations ("cell phone" and cellphone).  Using keywords when searching full text requires consideration of various words that express an idea or concept.

  • Subject Headings
  • Predetermined "controlled vocabulary" database editors apply to resources to describe topical coverage of content
  • Can retrieve more precise search results because every article assigned that subject heading will be retrieved.
  • Provide less flexibility in a search
  • Can be combined with a keyword search to focus search results.
  • TIP: Consult database subject heading list or subject headings assigned to relevant resources

what are the 3 main sources of literature review

Example 1: In EBSCO's Academic Search Complete, clicking on the "Subject Terms" tab provides access to the entire subject heading list used in the database.  It also allows a search for specific subject terms.

what are the 3 main sources of literature review

Example 2:  A subject term can be incorporated into a keyword search by clicking on the down arrow next to "Select a Field" and selecting "Subject Terms" from the dropdown list.  Also, notice how subject headings are listed below the resource title, providing another strategy for discovering subject headings used in the database.

When a search term is more than one word, enclose the phrase in quotation marks to retrieve more precise and accurate results.  Using quotation marks around a term will search it as a "chunk," searching for those particular words together in that order within the text of a resource. 

"cell phone"

"distracted driving"

"car accident"

TIP: In some databases, neglecting to enclose phrases in quotation marks will insert the AND Boolean connector between each word resulting in unintended search results.

Truncation provides an option to search for a root of a keyword in order to retrieve resources that include variations of that word.  This feature can be used to broaden search results, although some results may not be relevant.  To truncate a keyword, type an asterisk (*) following the root of the word.

For example:

what are the 3 main sources of literature review

Library databases provide a variety of tools to limit and refine search results.  Limiters provide the ability to limit search results to resources having specified characteristics including:

  • Resource type
  • Publication date
  • Geographic location

In both the EBSCO and ProQuest databases, the limiting tools are located in the left panel of the results page.

                                                 EBSCO                                                     ProQuest

what are the 3 main sources of literature review

The short video below provides a demonstration of how to use limiters to refine a list of search results.

Each resource in a library database is stored in a record.  In addition to the full-text of the resources, searchable Fields are attached that typically include:

  • Journal title
  • Date of Publication

Incorporating Fields into your search can assist in focusing and refining search results by limiting the results to those resources that include specific information in a particular field.

In both EBSCO and ProQuest databases, selecting the Advanced Search option will allow Fields to be included in a search.

For example, in the Advanced Search option in EBSCO's Academic Search Complete database, clicking on the down arrow next to "Select a Field" provides a list of fields that can be searched within that database.  Select the field and enter the information in the text box to the left to use this feature.

what are the 3 main sources of literature review

Stop words are short, commonly used words--articles, prepositions, and pronouns-- that are automatically dropped from a search.  Typical stop words include:

In library databases, a stop word will not be searched even if it is included in a phrase enclosed in quotation marks.  In some instances, a word will be substituted for the stop word to allow for the other words in the phrase to be searched in proximity to one another within the text of the resource.

For example, if you searched company of America, your result list will include these variatons:

  • company in America
  • company of America
  • company for America

Creating an Search String

This short video demonstrates how to create a search string -- keywords connected with Boolean operators -- to use in a library database search to retrieve relevant resources for any research assignment.

  • Database Search Menu Template Use this search menu template to plan a database search.
  • Next: Back to Research Help >>
  • Last Updated: May 7, 2024 2:33 PM
  • URL: https://guides.rasmussen.edu/LitReview
  • Library Homepage

Literature Review: The What, Why and How-to Guide: Evaluating Sources & Literature Reviews

  • Literature Reviews?
  • Strategies to Finding Sources
  • Keeping up with Research!
  • Evaluating Sources & Literature Reviews
  • Organizing for Writing
  • Writing Literature Review
  • Other Academic Writings

Evaluating Literature Reviews and Sources

  • Tips for Evaluating Sources (Print vs. Internet Sources) Excellent page that will guide you on what to ask to determine if your source is a reliable one. Check the other topics in the guide: Evaluating Bibliographic Citations and Evaluation During Reading on the left side menu.

Criteria to evaluate sources:

  • Authority : Who is the author? What are the author's credentials and areas of expertise? Is he or she affiliated with a university?
  • Usefulness : How this source related to your topic? How current or relevant it is to your topic?
  • Reliability : Does the information comes from a reliable, trusted source such as an academic journal?
  • Critically Analyzing Information Sources: Critical Appraisal and Analysis (Cornell University Library) Ten things to look for when you evaluate an information source.

Reading Critically

Reading critically (summary from how to read academic texts critically).

  • Who is the author? What is his/her standing in the field?
  • What is the author’s purpose? To offer advice, make practical suggestions, solve a specific problem, critique or clarify?
  • Note the experts in the field: are there specific names/labs that are frequently cited?
  • Pay attention to methodology: is it sound? what testing procedures, subjects, materials were used?
  • Note conflicting theories, methodologies, and results. Are there any assumptions being made by most/some researchers?
  • Theories: have they evolved over time?
  • Evaluate and synthesize the findings and conclusions. How does this study contribute to your project?
  • How to Read Academic Texts Critically Excellent document about how best to read critically academic articles and other texts.
  • How to Read an Academic Article This is an excellent paper that teach you how to read an academic paper, how to determine if it is something to set aside, or something to read deeply. Good advice to organize your literature for the Literature Review or just reading for classes.
  • << Previous: Keeping up with Research!
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  • Last Updated: Mar 5, 2024 11:44 AM
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Lau F, Kuziemsky C, editors. Handbook of eHealth Evaluation: An Evidence-based Approach [Internet]. Victoria (BC): University of Victoria; 2017 Feb 27.

Cover of Handbook of eHealth Evaluation: An Evidence-based Approach

Handbook of eHealth Evaluation: An Evidence-based Approach [Internet].

Chapter 9 methods for literature reviews.

Guy Paré and Spyros Kitsiou .

9.1. Introduction

Literature reviews play a critical role in scholarship because science remains, first and foremost, a cumulative endeavour ( vom Brocke et al., 2009 ). As in any academic discipline, rigorous knowledge syntheses are becoming indispensable in keeping up with an exponentially growing eHealth literature, assisting practitioners, academics, and graduate students in finding, evaluating, and synthesizing the contents of many empirical and conceptual papers. Among other methods, literature reviews are essential for: (a) identifying what has been written on a subject or topic; (b) determining the extent to which a specific research area reveals any interpretable trends or patterns; (c) aggregating empirical findings related to a narrow research question to support evidence-based practice; (d) generating new frameworks and theories; and (e) identifying topics or questions requiring more investigation ( Paré, Trudel, Jaana, & Kitsiou, 2015 ).

Literature reviews can take two major forms. The most prevalent one is the “literature review” or “background” section within a journal paper or a chapter in a graduate thesis. This section synthesizes the extant literature and usually identifies the gaps in knowledge that the empirical study addresses ( Sylvester, Tate, & Johnstone, 2013 ). It may also provide a theoretical foundation for the proposed study, substantiate the presence of the research problem, justify the research as one that contributes something new to the cumulated knowledge, or validate the methods and approaches for the proposed study ( Hart, 1998 ; Levy & Ellis, 2006 ).

The second form of literature review, which is the focus of this chapter, constitutes an original and valuable work of research in and of itself ( Paré et al., 2015 ). Rather than providing a base for a researcher’s own work, it creates a solid starting point for all members of the community interested in a particular area or topic ( Mulrow, 1987 ). The so-called “review article” is a journal-length paper which has an overarching purpose to synthesize the literature in a field, without collecting or analyzing any primary data ( Green, Johnson, & Adams, 2006 ).

When appropriately conducted, review articles represent powerful information sources for practitioners looking for state-of-the art evidence to guide their decision-making and work practices ( Paré et al., 2015 ). Further, high-quality reviews become frequently cited pieces of work which researchers seek out as a first clear outline of the literature when undertaking empirical studies ( Cooper, 1988 ; Rowe, 2014 ). Scholars who track and gauge the impact of articles have found that review papers are cited and downloaded more often than any other type of published article ( Cronin, Ryan, & Coughlan, 2008 ; Montori, Wilczynski, Morgan, Haynes, & Hedges, 2003 ; Patsopoulos, Analatos, & Ioannidis, 2005 ). The reason for their popularity may be the fact that reading the review enables one to have an overview, if not a detailed knowledge of the area in question, as well as references to the most useful primary sources ( Cronin et al., 2008 ). Although they are not easy to conduct, the commitment to complete a review article provides a tremendous service to one’s academic community ( Paré et al., 2015 ; Petticrew & Roberts, 2006 ). Most, if not all, peer-reviewed journals in the fields of medical informatics publish review articles of some type.

The main objectives of this chapter are fourfold: (a) to provide an overview of the major steps and activities involved in conducting a stand-alone literature review; (b) to describe and contrast the different types of review articles that can contribute to the eHealth knowledge base; (c) to illustrate each review type with one or two examples from the eHealth literature; and (d) to provide a series of recommendations for prospective authors of review articles in this domain.

9.2. Overview of the Literature Review Process and Steps

As explained in Templier and Paré (2015) , there are six generic steps involved in conducting a review article:

  • formulating the research question(s) and objective(s),
  • searching the extant literature,
  • screening for inclusion,
  • assessing the quality of primary studies,
  • extracting data, and
  • analyzing data.

Although these steps are presented here in sequential order, one must keep in mind that the review process can be iterative and that many activities can be initiated during the planning stage and later refined during subsequent phases ( Finfgeld-Connett & Johnson, 2013 ; Kitchenham & Charters, 2007 ).

Formulating the research question(s) and objective(s): As a first step, members of the review team must appropriately justify the need for the review itself ( Petticrew & Roberts, 2006 ), identify the review’s main objective(s) ( Okoli & Schabram, 2010 ), and define the concepts or variables at the heart of their synthesis ( Cooper & Hedges, 2009 ; Webster & Watson, 2002 ). Importantly, they also need to articulate the research question(s) they propose to investigate ( Kitchenham & Charters, 2007 ). In this regard, we concur with Jesson, Matheson, and Lacey (2011) that clearly articulated research questions are key ingredients that guide the entire review methodology; they underscore the type of information that is needed, inform the search for and selection of relevant literature, and guide or orient the subsequent analysis. Searching the extant literature: The next step consists of searching the literature and making decisions about the suitability of material to be considered in the review ( Cooper, 1988 ). There exist three main coverage strategies. First, exhaustive coverage means an effort is made to be as comprehensive as possible in order to ensure that all relevant studies, published and unpublished, are included in the review and, thus, conclusions are based on this all-inclusive knowledge base. The second type of coverage consists of presenting materials that are representative of most other works in a given field or area. Often authors who adopt this strategy will search for relevant articles in a small number of top-tier journals in a field ( Paré et al., 2015 ). In the third strategy, the review team concentrates on prior works that have been central or pivotal to a particular topic. This may include empirical studies or conceptual papers that initiated a line of investigation, changed how problems or questions were framed, introduced new methods or concepts, or engendered important debate ( Cooper, 1988 ). Screening for inclusion: The following step consists of evaluating the applicability of the material identified in the preceding step ( Levy & Ellis, 2006 ; vom Brocke et al., 2009 ). Once a group of potential studies has been identified, members of the review team must screen them to determine their relevance ( Petticrew & Roberts, 2006 ). A set of predetermined rules provides a basis for including or excluding certain studies. This exercise requires a significant investment on the part of researchers, who must ensure enhanced objectivity and avoid biases or mistakes. As discussed later in this chapter, for certain types of reviews there must be at least two independent reviewers involved in the screening process and a procedure to resolve disagreements must also be in place ( Liberati et al., 2009 ; Shea et al., 2009 ). Assessing the quality of primary studies: In addition to screening material for inclusion, members of the review team may need to assess the scientific quality of the selected studies, that is, appraise the rigour of the research design and methods. Such formal assessment, which is usually conducted independently by at least two coders, helps members of the review team refine which studies to include in the final sample, determine whether or not the differences in quality may affect their conclusions, or guide how they analyze the data and interpret the findings ( Petticrew & Roberts, 2006 ). Ascribing quality scores to each primary study or considering through domain-based evaluations which study components have or have not been designed and executed appropriately makes it possible to reflect on the extent to which the selected study addresses possible biases and maximizes validity ( Shea et al., 2009 ). Extracting data: The following step involves gathering or extracting applicable information from each primary study included in the sample and deciding what is relevant to the problem of interest ( Cooper & Hedges, 2009 ). Indeed, the type of data that should be recorded mainly depends on the initial research questions ( Okoli & Schabram, 2010 ). However, important information may also be gathered about how, when, where and by whom the primary study was conducted, the research design and methods, or qualitative/quantitative results ( Cooper & Hedges, 2009 ). Analyzing and synthesizing data : As a final step, members of the review team must collate, summarize, aggregate, organize, and compare the evidence extracted from the included studies. The extracted data must be presented in a meaningful way that suggests a new contribution to the extant literature ( Jesson et al., 2011 ). Webster and Watson (2002) warn researchers that literature reviews should be much more than lists of papers and should provide a coherent lens to make sense of extant knowledge on a given topic. There exist several methods and techniques for synthesizing quantitative (e.g., frequency analysis, meta-analysis) and qualitative (e.g., grounded theory, narrative analysis, meta-ethnography) evidence ( Dixon-Woods, Agarwal, Jones, Young, & Sutton, 2005 ; Thomas & Harden, 2008 ).

9.3. Types of Review Articles and Brief Illustrations

EHealth researchers have at their disposal a number of approaches and methods for making sense out of existing literature, all with the purpose of casting current research findings into historical contexts or explaining contradictions that might exist among a set of primary research studies conducted on a particular topic. Our classification scheme is largely inspired from Paré and colleagues’ (2015) typology. Below we present and illustrate those review types that we feel are central to the growth and development of the eHealth domain.

9.3.1. Narrative Reviews

The narrative review is the “traditional” way of reviewing the extant literature and is skewed towards a qualitative interpretation of prior knowledge ( Sylvester et al., 2013 ). Put simply, a narrative review attempts to summarize or synthesize what has been written on a particular topic but does not seek generalization or cumulative knowledge from what is reviewed ( Davies, 2000 ; Green et al., 2006 ). Instead, the review team often undertakes the task of accumulating and synthesizing the literature to demonstrate the value of a particular point of view ( Baumeister & Leary, 1997 ). As such, reviewers may selectively ignore or limit the attention paid to certain studies in order to make a point. In this rather unsystematic approach, the selection of information from primary articles is subjective, lacks explicit criteria for inclusion and can lead to biased interpretations or inferences ( Green et al., 2006 ). There are several narrative reviews in the particular eHealth domain, as in all fields, which follow such an unstructured approach ( Silva et al., 2015 ; Paul et al., 2015 ).

Despite these criticisms, this type of review can be very useful in gathering together a volume of literature in a specific subject area and synthesizing it. As mentioned above, its primary purpose is to provide the reader with a comprehensive background for understanding current knowledge and highlighting the significance of new research ( Cronin et al., 2008 ). Faculty like to use narrative reviews in the classroom because they are often more up to date than textbooks, provide a single source for students to reference, and expose students to peer-reviewed literature ( Green et al., 2006 ). For researchers, narrative reviews can inspire research ideas by identifying gaps or inconsistencies in a body of knowledge, thus helping researchers to determine research questions or formulate hypotheses. Importantly, narrative reviews can also be used as educational articles to bring practitioners up to date with certain topics of issues ( Green et al., 2006 ).

Recently, there have been several efforts to introduce more rigour in narrative reviews that will elucidate common pitfalls and bring changes into their publication standards. Information systems researchers, among others, have contributed to advancing knowledge on how to structure a “traditional” review. For instance, Levy and Ellis (2006) proposed a generic framework for conducting such reviews. Their model follows the systematic data processing approach comprised of three steps, namely: (a) literature search and screening; (b) data extraction and analysis; and (c) writing the literature review. They provide detailed and very helpful instructions on how to conduct each step of the review process. As another methodological contribution, vom Brocke et al. (2009) offered a series of guidelines for conducting literature reviews, with a particular focus on how to search and extract the relevant body of knowledge. Last, Bandara, Miskon, and Fielt (2011) proposed a structured, predefined and tool-supported method to identify primary studies within a feasible scope, extract relevant content from identified articles, synthesize and analyze the findings, and effectively write and present the results of the literature review. We highly recommend that prospective authors of narrative reviews consult these useful sources before embarking on their work.

Darlow and Wen (2015) provide a good example of a highly structured narrative review in the eHealth field. These authors synthesized published articles that describe the development process of mobile health ( m-health ) interventions for patients’ cancer care self-management. As in most narrative reviews, the scope of the research questions being investigated is broad: (a) how development of these systems are carried out; (b) which methods are used to investigate these systems; and (c) what conclusions can be drawn as a result of the development of these systems. To provide clear answers to these questions, a literature search was conducted on six electronic databases and Google Scholar . The search was performed using several terms and free text words, combining them in an appropriate manner. Four inclusion and three exclusion criteria were utilized during the screening process. Both authors independently reviewed each of the identified articles to determine eligibility and extract study information. A flow diagram shows the number of studies identified, screened, and included or excluded at each stage of study selection. In terms of contributions, this review provides a series of practical recommendations for m-health intervention development.

9.3.2. Descriptive or Mapping Reviews

The primary goal of a descriptive review is to determine the extent to which a body of knowledge in a particular research topic reveals any interpretable pattern or trend with respect to pre-existing propositions, theories, methodologies or findings ( King & He, 2005 ; Paré et al., 2015 ). In contrast with narrative reviews, descriptive reviews follow a systematic and transparent procedure, including searching, screening and classifying studies ( Petersen, Vakkalanka, & Kuzniarz, 2015 ). Indeed, structured search methods are used to form a representative sample of a larger group of published works ( Paré et al., 2015 ). Further, authors of descriptive reviews extract from each study certain characteristics of interest, such as publication year, research methods, data collection techniques, and direction or strength of research outcomes (e.g., positive, negative, or non-significant) in the form of frequency analysis to produce quantitative results ( Sylvester et al., 2013 ). In essence, each study included in a descriptive review is treated as the unit of analysis and the published literature as a whole provides a database from which the authors attempt to identify any interpretable trends or draw overall conclusions about the merits of existing conceptualizations, propositions, methods or findings ( Paré et al., 2015 ). In doing so, a descriptive review may claim that its findings represent the state of the art in a particular domain ( King & He, 2005 ).

In the fields of health sciences and medical informatics, reviews that focus on examining the range, nature and evolution of a topic area are described by Anderson, Allen, Peckham, and Goodwin (2008) as mapping reviews . Like descriptive reviews, the research questions are generic and usually relate to publication patterns and trends. There is no preconceived plan to systematically review all of the literature although this can be done. Instead, researchers often present studies that are representative of most works published in a particular area and they consider a specific time frame to be mapped.

An example of this approach in the eHealth domain is offered by DeShazo, Lavallie, and Wolf (2009). The purpose of this descriptive or mapping review was to characterize publication trends in the medical informatics literature over a 20-year period (1987 to 2006). To achieve this ambitious objective, the authors performed a bibliometric analysis of medical informatics citations indexed in medline using publication trends, journal frequencies, impact factors, Medical Subject Headings (MeSH) term frequencies, and characteristics of citations. Findings revealed that there were over 77,000 medical informatics articles published during the covered period in numerous journals and that the average annual growth rate was 12%. The MeSH term analysis also suggested a strong interdisciplinary trend. Finally, average impact scores increased over time with two notable growth periods. Overall, patterns in research outputs that seem to characterize the historic trends and current components of the field of medical informatics suggest it may be a maturing discipline (DeShazo et al., 2009).

9.3.3. Scoping Reviews

Scoping reviews attempt to provide an initial indication of the potential size and nature of the extant literature on an emergent topic (Arksey & O’Malley, 2005; Daudt, van Mossel, & Scott, 2013 ; Levac, Colquhoun, & O’Brien, 2010). A scoping review may be conducted to examine the extent, range and nature of research activities in a particular area, determine the value of undertaking a full systematic review (discussed next), or identify research gaps in the extant literature ( Paré et al., 2015 ). In line with their main objective, scoping reviews usually conclude with the presentation of a detailed research agenda for future works along with potential implications for both practice and research.

Unlike narrative and descriptive reviews, the whole point of scoping the field is to be as comprehensive as possible, including grey literature (Arksey & O’Malley, 2005). Inclusion and exclusion criteria must be established to help researchers eliminate studies that are not aligned with the research questions. It is also recommended that at least two independent coders review abstracts yielded from the search strategy and then the full articles for study selection ( Daudt et al., 2013 ). The synthesized evidence from content or thematic analysis is relatively easy to present in tabular form (Arksey & O’Malley, 2005; Thomas & Harden, 2008 ).

One of the most highly cited scoping reviews in the eHealth domain was published by Archer, Fevrier-Thomas, Lokker, McKibbon, and Straus (2011) . These authors reviewed the existing literature on personal health record ( phr ) systems including design, functionality, implementation, applications, outcomes, and benefits. Seven databases were searched from 1985 to March 2010. Several search terms relating to phr s were used during this process. Two authors independently screened titles and abstracts to determine inclusion status. A second screen of full-text articles, again by two independent members of the research team, ensured that the studies described phr s. All in all, 130 articles met the criteria and their data were extracted manually into a database. The authors concluded that although there is a large amount of survey, observational, cohort/panel, and anecdotal evidence of phr benefits and satisfaction for patients, more research is needed to evaluate the results of phr implementations. Their in-depth analysis of the literature signalled that there is little solid evidence from randomized controlled trials or other studies through the use of phr s. Hence, they suggested that more research is needed that addresses the current lack of understanding of optimal functionality and usability of these systems, and how they can play a beneficial role in supporting patient self-management ( Archer et al., 2011 ).

9.3.4. Forms of Aggregative Reviews

Healthcare providers, practitioners, and policy-makers are nowadays overwhelmed with large volumes of information, including research-based evidence from numerous clinical trials and evaluation studies, assessing the effectiveness of health information technologies and interventions ( Ammenwerth & de Keizer, 2004 ; Deshazo et al., 2009 ). It is unrealistic to expect that all these disparate actors will have the time, skills, and necessary resources to identify the available evidence in the area of their expertise and consider it when making decisions. Systematic reviews that involve the rigorous application of scientific strategies aimed at limiting subjectivity and bias (i.e., systematic and random errors) can respond to this challenge.

Systematic reviews attempt to aggregate, appraise, and synthesize in a single source all empirical evidence that meet a set of previously specified eligibility criteria in order to answer a clearly formulated and often narrow research question on a particular topic of interest to support evidence-based practice ( Liberati et al., 2009 ). They adhere closely to explicit scientific principles ( Liberati et al., 2009 ) and rigorous methodological guidelines (Higgins & Green, 2008) aimed at reducing random and systematic errors that can lead to deviations from the truth in results or inferences. The use of explicit methods allows systematic reviews to aggregate a large body of research evidence, assess whether effects or relationships are in the same direction and of the same general magnitude, explain possible inconsistencies between study results, and determine the strength of the overall evidence for every outcome of interest based on the quality of included studies and the general consistency among them ( Cook, Mulrow, & Haynes, 1997 ). The main procedures of a systematic review involve:

  • Formulating a review question and developing a search strategy based on explicit inclusion criteria for the identification of eligible studies (usually described in the context of a detailed review protocol).
  • Searching for eligible studies using multiple databases and information sources, including grey literature sources, without any language restrictions.
  • Selecting studies, extracting data, and assessing risk of bias in a duplicate manner using two independent reviewers to avoid random or systematic errors in the process.
  • Analyzing data using quantitative or qualitative methods.
  • Presenting results in summary of findings tables.
  • Interpreting results and drawing conclusions.

Many systematic reviews, but not all, use statistical methods to combine the results of independent studies into a single quantitative estimate or summary effect size. Known as meta-analyses , these reviews use specific data extraction and statistical techniques (e.g., network, frequentist, or Bayesian meta-analyses) to calculate from each study by outcome of interest an effect size along with a confidence interval that reflects the degree of uncertainty behind the point estimate of effect ( Borenstein, Hedges, Higgins, & Rothstein, 2009 ; Deeks, Higgins, & Altman, 2008 ). Subsequently, they use fixed or random-effects analysis models to combine the results of the included studies, assess statistical heterogeneity, and calculate a weighted average of the effect estimates from the different studies, taking into account their sample sizes. The summary effect size is a value that reflects the average magnitude of the intervention effect for a particular outcome of interest or, more generally, the strength of a relationship between two variables across all studies included in the systematic review. By statistically combining data from multiple studies, meta-analyses can create more precise and reliable estimates of intervention effects than those derived from individual studies alone, when these are examined independently as discrete sources of information.

The review by Gurol-Urganci, de Jongh, Vodopivec-Jamsek, Atun, and Car (2013) on the effects of mobile phone messaging reminders for attendance at healthcare appointments is an illustrative example of a high-quality systematic review with meta-analysis. Missed appointments are a major cause of inefficiency in healthcare delivery with substantial monetary costs to health systems. These authors sought to assess whether mobile phone-based appointment reminders delivered through Short Message Service ( sms ) or Multimedia Messaging Service ( mms ) are effective in improving rates of patient attendance and reducing overall costs. To this end, they conducted a comprehensive search on multiple databases using highly sensitive search strategies without language or publication-type restrictions to identify all rct s that are eligible for inclusion. In order to minimize the risk of omitting eligible studies not captured by the original search, they supplemented all electronic searches with manual screening of trial registers and references contained in the included studies. Study selection, data extraction, and risk of bias assessments were performed inde­­pen­dently by two coders using standardized methods to ensure consistency and to eliminate potential errors. Findings from eight rct s involving 6,615 participants were pooled into meta-analyses to calculate the magnitude of effects that mobile text message reminders have on the rate of attendance at healthcare appointments compared to no reminders and phone call reminders.

Meta-analyses are regarded as powerful tools for deriving meaningful conclusions. However, there are situations in which it is neither reasonable nor appropriate to pool studies together using meta-analytic methods simply because there is extensive clinical heterogeneity between the included studies or variation in measurement tools, comparisons, or outcomes of interest. In these cases, systematic reviews can use qualitative synthesis methods such as vote counting, content analysis, classification schemes and tabulations, as an alternative approach to narratively synthesize the results of the independent studies included in the review. This form of review is known as qualitative systematic review.

A rigorous example of one such review in the eHealth domain is presented by Mickan, Atherton, Roberts, Heneghan, and Tilson (2014) on the use of handheld computers by healthcare professionals and their impact on access to information and clinical decision-making. In line with the methodological guide­lines for systematic reviews, these authors: (a) developed and registered with prospero ( www.crd.york.ac.uk/ prospero / ) an a priori review protocol; (b) conducted comprehensive searches for eligible studies using multiple databases and other supplementary strategies (e.g., forward searches); and (c) subsequently carried out study selection, data extraction, and risk of bias assessments in a duplicate manner to eliminate potential errors in the review process. Heterogeneity between the included studies in terms of reported outcomes and measures precluded the use of meta-analytic methods. To this end, the authors resorted to using narrative analysis and synthesis to describe the effectiveness of handheld computers on accessing information for clinical knowledge, adherence to safety and clinical quality guidelines, and diagnostic decision-making.

In recent years, the number of systematic reviews in the field of health informatics has increased considerably. Systematic reviews with discordant findings can cause great confusion and make it difficult for decision-makers to interpret the review-level evidence ( Moher, 2013 ). Therefore, there is a growing need for appraisal and synthesis of prior systematic reviews to ensure that decision-making is constantly informed by the best available accumulated evidence. Umbrella reviews , also known as overviews of systematic reviews, are tertiary types of evidence synthesis that aim to accomplish this; that is, they aim to compare and contrast findings from multiple systematic reviews and meta-analyses ( Becker & Oxman, 2008 ). Umbrella reviews generally adhere to the same principles and rigorous methodological guidelines used in systematic reviews. However, the unit of analysis in umbrella reviews is the systematic review rather than the primary study ( Becker & Oxman, 2008 ). Unlike systematic reviews that have a narrow focus of inquiry, umbrella reviews focus on broader research topics for which there are several potential interventions ( Smith, Devane, Begley, & Clarke, 2011 ). A recent umbrella review on the effects of home telemonitoring interventions for patients with heart failure critically appraised, compared, and synthesized evidence from 15 systematic reviews to investigate which types of home telemonitoring technologies and forms of interventions are more effective in reducing mortality and hospital admissions ( Kitsiou, Paré, & Jaana, 2015 ).

9.3.5. Realist Reviews

Realist reviews are theory-driven interpretative reviews developed to inform, enhance, or supplement conventional systematic reviews by making sense of heterogeneous evidence about complex interventions applied in diverse contexts in a way that informs policy decision-making ( Greenhalgh, Wong, Westhorp, & Pawson, 2011 ). They originated from criticisms of positivist systematic reviews which centre on their “simplistic” underlying assumptions ( Oates, 2011 ). As explained above, systematic reviews seek to identify causation. Such logic is appropriate for fields like medicine and education where findings of randomized controlled trials can be aggregated to see whether a new treatment or intervention does improve outcomes. However, many argue that it is not possible to establish such direct causal links between interventions and outcomes in fields such as social policy, management, and information systems where for any intervention there is unlikely to be a regular or consistent outcome ( Oates, 2011 ; Pawson, 2006 ; Rousseau, Manning, & Denyer, 2008 ).

To circumvent these limitations, Pawson, Greenhalgh, Harvey, and Walshe (2005) have proposed a new approach for synthesizing knowledge that seeks to unpack the mechanism of how “complex interventions” work in particular contexts. The basic research question — what works? — which is usually associated with systematic reviews changes to: what is it about this intervention that works, for whom, in what circumstances, in what respects and why? Realist reviews have no particular preference for either quantitative or qualitative evidence. As a theory-building approach, a realist review usually starts by articulating likely underlying mechanisms and then scrutinizes available evidence to find out whether and where these mechanisms are applicable ( Shepperd et al., 2009 ). Primary studies found in the extant literature are viewed as case studies which can test and modify the initial theories ( Rousseau et al., 2008 ).

The main objective pursued in the realist review conducted by Otte-Trojel, de Bont, Rundall, and van de Klundert (2014) was to examine how patient portals contribute to health service delivery and patient outcomes. The specific goals were to investigate how outcomes are produced and, most importantly, how variations in outcomes can be explained. The research team started with an exploratory review of background documents and research studies to identify ways in which patient portals may contribute to health service delivery and patient outcomes. The authors identified six main ways which represent “educated guesses” to be tested against the data in the evaluation studies. These studies were identified through a formal and systematic search in four databases between 2003 and 2013. Two members of the research team selected the articles using a pre-established list of inclusion and exclusion criteria and following a two-step procedure. The authors then extracted data from the selected articles and created several tables, one for each outcome category. They organized information to bring forward those mechanisms where patient portals contribute to outcomes and the variation in outcomes across different contexts.

9.3.6. Critical Reviews

Lastly, critical reviews aim to provide a critical evaluation and interpretive analysis of existing literature on a particular topic of interest to reveal strengths, weaknesses, contradictions, controversies, inconsistencies, and/or other important issues with respect to theories, hypotheses, research methods or results ( Baumeister & Leary, 1997 ; Kirkevold, 1997 ). Unlike other review types, critical reviews attempt to take a reflective account of the research that has been done in a particular area of interest, and assess its credibility by using appraisal instruments or critical interpretive methods. In this way, critical reviews attempt to constructively inform other scholars about the weaknesses of prior research and strengthen knowledge development by giving focus and direction to studies for further improvement ( Kirkevold, 1997 ).

Kitsiou, Paré, and Jaana (2013) provide an example of a critical review that assessed the methodological quality of prior systematic reviews of home telemonitoring studies for chronic patients. The authors conducted a comprehensive search on multiple databases to identify eligible reviews and subsequently used a validated instrument to conduct an in-depth quality appraisal. Results indicate that the majority of systematic reviews in this particular area suffer from important methodological flaws and biases that impair their internal validity and limit their usefulness for clinical and decision-making purposes. To this end, they provide a number of recommendations to strengthen knowledge development towards improving the design and execution of future reviews on home telemonitoring.

9.4. Summary

Table 9.1 outlines the main types of literature reviews that were described in the previous sub-sections and summarizes the main characteristics that distinguish one review type from another. It also includes key references to methodological guidelines and useful sources that can be used by eHealth scholars and researchers for planning and developing reviews.

Table 9.1. Typology of Literature Reviews (adapted from Paré et al., 2015).

Typology of Literature Reviews (adapted from Paré et al., 2015).

As shown in Table 9.1 , each review type addresses different kinds of research questions or objectives, which subsequently define and dictate the methods and approaches that need to be used to achieve the overarching goal(s) of the review. For example, in the case of narrative reviews, there is greater flexibility in searching and synthesizing articles ( Green et al., 2006 ). Researchers are often relatively free to use a diversity of approaches to search, identify, and select relevant scientific articles, describe their operational characteristics, present how the individual studies fit together, and formulate conclusions. On the other hand, systematic reviews are characterized by their high level of systematicity, rigour, and use of explicit methods, based on an “a priori” review plan that aims to minimize bias in the analysis and synthesis process (Higgins & Green, 2008). Some reviews are exploratory in nature (e.g., scoping/mapping reviews), whereas others may be conducted to discover patterns (e.g., descriptive reviews) or involve a synthesis approach that may include the critical analysis of prior research ( Paré et al., 2015 ). Hence, in order to select the most appropriate type of review, it is critical to know before embarking on a review project, why the research synthesis is conducted and what type of methods are best aligned with the pursued goals.

9.5. Concluding Remarks

In light of the increased use of evidence-based practice and research generating stronger evidence ( Grady et al., 2011 ; Lyden et al., 2013 ), review articles have become essential tools for summarizing, synthesizing, integrating or critically appraising prior knowledge in the eHealth field. As mentioned earlier, when rigorously conducted review articles represent powerful information sources for eHealth scholars and practitioners looking for state-of-the-art evidence. The typology of literature reviews we used herein will allow eHealth researchers, graduate students and practitioners to gain a better understanding of the similarities and differences between review types.

We must stress that this classification scheme does not privilege any specific type of review as being of higher quality than another ( Paré et al., 2015 ). As explained above, each type of review has its own strengths and limitations. Having said that, we realize that the methodological rigour of any review — be it qualitative, quantitative or mixed — is a critical aspect that should be considered seriously by prospective authors. In the present context, the notion of rigour refers to the reliability and validity of the review process described in section 9.2. For one thing, reliability is related to the reproducibility of the review process and steps, which is facilitated by a comprehensive documentation of the literature search process, extraction, coding and analysis performed in the review. Whether the search is comprehensive or not, whether it involves a methodical approach for data extraction and synthesis or not, it is important that the review documents in an explicit and transparent manner the steps and approach that were used in the process of its development. Next, validity characterizes the degree to which the review process was conducted appropriately. It goes beyond documentation and reflects decisions related to the selection of the sources, the search terms used, the period of time covered, the articles selected in the search, and the application of backward and forward searches ( vom Brocke et al., 2009 ). In short, the rigour of any review article is reflected by the explicitness of its methods (i.e., transparency) and the soundness of the approach used. We refer those interested in the concepts of rigour and quality to the work of Templier and Paré (2015) which offers a detailed set of methodological guidelines for conducting and evaluating various types of review articles.

To conclude, our main objective in this chapter was to demystify the various types of literature reviews that are central to the continuous development of the eHealth field. It is our hope that our descriptive account will serve as a valuable source for those conducting, evaluating or using reviews in this important and growing domain.

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  • Introduction
  • Overview of the Literature Review Process and Steps
  • Types of Review Articles and Brief Illustrations
  • Concluding Remarks

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The Research Proposal

83 Components of the Literature Review

Krathwohl (2005) suggests and describes a variety of components to include in a research proposal.  The following sections present these components in a suggested template for you to follow in the preparation of your research proposal.

Introduction

The introduction sets the tone for what follows in your research proposal – treat it as the initial pitch of your idea.  After reading the introduction your reader should:

  • Understand what it is you want to do;
  • Have a sense of your passion for the topic;
  • Be excited about the study´s possible outcomes.

As you begin writing your research proposal it is helpful to think of the introduction as a narrative of what it is you want to do, written in one to three paragraphs.  Within those one to three paragraphs, it is important to briefly answer the following questions:

  • What is the central research problem?
  • How is the topic of your research proposal related to the problem?
  • What methods will you utilize to analyze the research problem?
  • Why is it important to undertake this research? What is the significance of your proposed research?  Why are the outcomes of your proposed research important, and to whom or to what are they important?

Note : You may be asked by your instructor to include an abstract with your research proposal.  In such cases, an abstract should provide an overview of what it is you plan to study, your main research question, a brief explanation of your methods to answer the research question, and your expected findings. All of this information must be carefully crafted in 150 to 250 words.  A word of advice is to save the writing of your abstract until the very end of your research proposal preparation.  If you are asked to provide an abstract, you should include 5-7 key words that are of most relevance to your study. List these in order of relevance.

Background and significance

The purpose of this section is to explain the context of your proposal and to describe, in detail, why it is important to undertake this research. Assume that the person or people who will read your research proposal know nothing or very little about the research problem.  While you do not need to include all knowledge you have learned about your topic in this section, it is important to ensure that you include the most relevant material that will help to explain the goals of your research.

While there are no hard and fast rules, you should attempt to address some or all of the following key points:

  • State the research problem and provide a more thorough explanation about the purpose of the study than what you stated in the introduction.
  • Present the rationale for the proposed research study. Clearly indicate why this research is worth doing.  Answer the “so what?” question.
  • Describe the major issues or problems to be addressed by your research. Do not forget to explain how and in what ways your proposed research builds upon previous related research.
  • Explain how you plan to go about conducting your research.
  • Clearly identify the key or most relevant sources of research you intend to use and explain how they will contribute to your analysis of the topic.
  • Set the boundaries of your proposed research, in order to provide a clear focus. Where appropriate, state not only what you will study, but what will be excluded from your study.
  • Provide clear definitions of key concepts and terms. As key concepts and terms often have numerous definitions, make sure you state which definition you will be utilizing in your research.

Literature Review

This is the most time-consuming aspect in the preparation of your research proposal and it is a key component of the research proposal. As described in Chapter 5 , the literature review provides the background to your study and demonstrates the significance of the proposed research. Specifically, it is a review and synthesis of prior research that is related to the problem you are setting forth to investigate.  Essentially, your goal in the literature review is to place your research study within the larger whole of what has been studied in the past, while demonstrating to your reader that your work is original, innovative, and adds to the larger whole.

As the literature review is information dense, it is essential that this section be intelligently structured to enable your reader to grasp the key arguments underpinning your study. However, this can be easier to state and harder to do, simply due to the fact there is usually a plethora of related research to sift through. Consequently, a good strategy for writing the literature review is to break the literature into conceptual categories or themes, rather than attempting to describe various groups of literature you reviewed.  Chapter V, “ The Literature Review ,” describes a variety of methods to help you organize the themes.

Here are some suggestions on how to approach the writing of your literature review:

  • Think about what questions other researchers have asked, what methods they used, what they found, and what they recommended based upon their findings.
  • Do not be afraid to challenge previous related research findings and/or conclusions.
  • Assess what you believe to be missing from previous research and explain how your research fills in this gap and/or extends previous research

It is important to note that a significant challenge related to undertaking a literature review is knowing when to stop.  As such, it is important to know how to know when you have uncovered the key conceptual categories underlying your research topic.  Generally, when you start to see repetition in the conclusions or recommendations, you can have confidence that you have covered all of the significant conceptual categories in your literature review.  However, it is also important to acknowledge that researchers often find themselves returning to the literature as they collect and analyze their data.  For example, an unexpected finding may develop as one collects and/or analyzes the data and it is important to take the time to step back and review the literature again, to ensure that no other researchers have found a similar finding.  This may include looking to research outside your field.

This situation occurred with one of the authors of this textbook´s research related to community resilience.  During the interviews, the researchers heard many participants discuss individual resilience factors and how they believed these individual factors helped make the community more resilient, overall.  Sheppard and Williams (2016) had not discovered these individual factors in their original literature review on community and environmental resilience. However, when they returned to the literature to search for individual resilience factors, they discovered a small body of literature in the child and youth psychology field. Consequently, Sheppard and Williams had to go back and add a new section to their literature review on individual resilience factors. Interestingly, their research appeared to be the first research to link individual resilience factors with community resilience factors.

Research design and methods

The objective of this section of the research proposal is to convince the reader that your overall research design and methods of analysis will enable you to solve the research problem you have identified and also enable you to accurately and effectively interpret the results of your research. Consequently, it is critical that the research design and methods section is well-written, clear, and logically organized.  This demonstrates to your reader that you know what you are going to do and how you are going to do it.  Overall, you want to leave your reader feeling confident that you have what it takes to get this research study completed in a timely fashion.

Essentially, this section of the research proposal should be clearly tied to the specific objectives of your study; however, it is also important to draw upon and include examples from the literature review that relate to your design and intended methods.  In other words, you must clearly demonstrate how your study utilizes and builds upon past studies, as it relates to the research design and intended methods.  For example, what methods have been used by other researchers in similar studies?

While it is important to consider the methods that other researchers have employed, it is equally important, if not more so, to consider what methods have not been employed but could be.  Remember, the methods section is not simply a list of tasks to be undertaken. It is also an argument as to why and how the tasks you have outlined will help you investigate the research problem and answer your research question(s).

Tips for writing the research design and methods section:

  • Specify the methodological approaches you intend to employ to obtain information and the techniques you will use to analyze the data.
  • Specify the research operations you will undertake and he way you will interpret the results of those operations in relation to the research problem.
  • Go beyond stating what you hope to achieve through the methods you have chosen. State how you will actually do the methods (i.e. coding interview text, running regression analysis, etc.).
  • Anticipate and acknowledge any potential barriers you may encounter when undertaking your research and describe how you will address these barriers.
  • Explain where you believe you will find challenges related to data collection, including access to participants and information.

Preliminary suppositions and implications

The purpose of this section is to argue how and in what ways you anticipate that your research will refine, revise, or extend existing knowledge in the area of your study. Depending upon the aims and objectives of your study, you should also discuss how your anticipated findings may impact future research.  For example, is it possible that your research may lead to a new policy, new theoretical understanding, or a new method for analyzing data?  How might your study influence future studies?  What might your study mean for future practitioners working in the field?  Who or what may benefit from your study?  How might your study contribute to social, economic, environmental issues?  While it is important to think about and discuss possibilities such as these, it is equally important to be realistic in stating your anticipated findings.  In other words, you do not want to delve into idle speculation.  Rather, the purpose here is to reflect upon gaps in the current body of literature and to describe how and in what ways you anticipate your research will begin to fill in some or all of those gaps.

The conclusion reiterates the importance and significance of your research proposal and it provides a brief summary of the entire proposed study.  Essentially, this section should only be one or two paragraphs in length. Here is a potential outline for your conclusion:

  • Discuss why the study should be done. Specifically discuss how you expect your study will advance existing knowledge and how your study is unique.
  • Explain the specific purpose of the study and the research questions that the study will answer.
  • Explain why the research design and methods chosen for this study are appropriate, and why other design and methods were not chosen.
  • State the potential implications you expect to emerge from your proposed study,
  • Provide a sense of how your study fits within the broader scholarship currently in existence related to the research problem.

As with any scholarly research paper, you must cite the sources you used in composing your research proposal.  In a research proposal, this can take two forms: a reference list or a bibliography.  A reference list does what the name suggests, it lists the literature you referenced in the body of your research proposal.  All references in the reference list, must appear in the body of the research proposal.  Remember, it is not acceptable to say “as cited in …”  As a researcher you must always go to the original source and check it for yourself.  Many errors are made in referencing, even by top researchers, and so it is important not to perpetuate an error made by someone else. While this can be time consuming, it is the proper way to undertake a literature review.

In contrast, a bibliography , is a list of everything you used or cited in your research proposal, with additional citations to any key sources relevant to understanding the research problem.  In other words, sources cited in your bibliography may not necessarily appear in the body of your research proposal.  Make sure you check with your instructor to see which of the two you are expected to produce.

Overall, your list of citations should be a testament to the fact that you have done a sufficient level of preliminary research to ensure that your project will complement, but not duplicate, previous research efforts. For social sciences, the reference list or bibliography should be prepared in American Psychological Association (APA) referencing format. Usually, the reference list (or bibliography) is not included in the word count of the research proposal. Again, make sure you check with your instructor to confirm.

An Introduction to Research Methods in Sociology Copyright © 2019 by Valerie A. Sheppard is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License , except where otherwise noted.

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  1. How to Write a Literature Review

    Examples of literature reviews. Step 1 - Search for relevant literature. Step 2 - Evaluate and select sources. Step 3 - Identify themes, debates, and gaps. Step 4 - Outline your literature review's structure. Step 5 - Write your literature review.

  2. Literature review sources

    Sources for literature review and examples. Generally, your literature review should integrate a wide range of sources such as: Books. Textbooks remain as the most important source to find models and theories related to the research area. Research the most respected authorities in your selected research area and find the latest editions of ...

  3. 5. The Literature Review

    A literature review may consist of simply a summary of key sources, but in the social sciences, a literature review usually has an organizational pattern and combines both summary and synthesis, often within specific conceptual categories.A summary is a recap of the important information of the source, but a synthesis is a re-organization, or a reshuffling, of that information in a way that ...

  4. Writing a Literature Review

    A literature review is a document or section of a document that collects key sources on a topic and discusses those sources in conversation with each other (also called synthesis ). The lit review is an important genre in many disciplines, not just literature (i.e., the study of works of literature such as novels and plays).

  5. What is a Literature Review?

    A literature review is a survey of scholarly sources on a specific topic. It provides an overview of current knowledge, allowing you to identify relevant theories, methods, and gaps in the existing research. There are five key steps to writing a literature review: Search for relevant literature. Evaluate sources. Identify themes, debates and gaps.

  6. Literature Review: The What, Why and How-to Guide

    What kinds of literature reviews are written? Narrative review: The purpose of this type of review is to describe the current state of the research on a specific topic/research and to offer a critical analysis of the literature reviewed. Studies are grouped by research/theoretical categories, and themes and trends, strengths and weakness, and gaps are identified.

  7. Literature Reviews

    A literature review discusses published information in a particular subject area, and sometimes information in a particular subject area within a certain time period. A literature review can be just a simple summary of the sources, but it usually has an organizational pattern and combines both summary and synthesis.

  8. Guidance on Conducting a Systematic Literature Review

    A successful review involves three major stages: planning the review, conducting the review, and reporting the review (Kitchenham and Charters 2007; ... There are three major sources to find literature: (1) electronic databases; (2) backward searching; and (3) forward searching.

  9. How To Write A Literature Review

    1. Outline and identify the purpose of a literature review. As a first step on how to write a literature review, you must know what the research question or topic is and what shape you want your literature review to take. Ensure you understand the research topic inside out, or else seek clarifications.

  10. Literature Review Research

    Literature Review is a comprehensive survey of the works published in a particular field of study or line of research, usually over a specific period of time, in the form of an in-depth, critical bibliographic essay or annotated list in which attention is drawn to the most significant works. Also, we can define a literature review as the ...

  11. What is a literature review?

    A literature or narrative review is a comprehensive review and analysis of the published literature on a specific topic or research question. The literature that is reviewed contains: books, articles, academic articles, conference proceedings, association papers, and dissertations. It contains the most pertinent studies and points to important ...

  12. Ten Simple Rules for Writing a Literature Review

    Literature reviews are in great demand in most scientific fields. Their need stems from the ever-increasing output of scientific publications .For example, compared to 1991, in 2008 three, eight, and forty times more papers were indexed in Web of Science on malaria, obesity, and biodiversity, respectively .Given such mountains of papers, scientists cannot be expected to examine in detail every ...

  13. Literature Review: Lit Review Sources

    Primary source: Usually a report by the original researchers of a study (unfiltered sources) Secondary source: Description or summary by somebody other than the original researcher, e.g. a review article (filtered sources) Conceptual/theoretical: Papers concerned with description or analysis of theories or concepts associated with the topic.

  14. Writing a literature review

    Writing a literature review requires a range of skills to gather, sort, evaluate and summarise peer-reviewed published data into a relevant and informative unbiased narrative. Digital access to research papers, academic texts, review articles, reference databases and public data sets are all sources of information that are available to enrich ...

  15. Steps in Conducting a Literature Review

    A literature review is important because it: Explains the background of research on a topic. Demonstrates why a topic is significant to a subject area. Discovers relationships between research studies/ideas. Identifies major themes, concepts, and researchers on a topic. Identifies critical gaps and points of disagreement.

  16. Literature Reviews

    Structure. The three elements of a literature review are introduction, body, and conclusion. Introduction. Define the topic of the literature review, including any terminology. Introduce the central theme and organization of the literature review. Summarize the state of research on the topic. Frame the literature review with your research question.

  17. Strategies to Find Sources

    Finding sources (scholarly articles, research books, dissertations, etc.) for your literature review is part of the research process. This process is iterative, meaning you repeat and modify searches until you have gathered enough sources for your project. The main steps in this research process are:

  18. Researching for your literature review: Literature sources

    A good quality literature review involves searching a number of databases individually. The most common method is to search a combination of large inter-disciplinary databases such as Scopus & Web of Science Core Collection, and some subject-specific databases (such as PsycInfo or EconLit etc.). The Library databases are an excellent place to ...

  19. Literature Review Guide

    A literature review explores all sides of the research topic and evaluates all positions and conclusions achieved through the scientific research process even though some conclusions may conflict partially or completely. From the Online Library. Conducting Your Literature Review by Susanne Hempel. ISBN: 9781433830921.

  20. Evaluating Sources & Literature Reviews

    A good literature review evaluates a wide variety of sources (academic articles, scholarly books, government/NGO reports). It also evaluates literature reviews that study similar topics. This page offers you a list of resources and tips on how to evaluate the sources that you may use to write your review.

  21. Primary, Secondary and Tertiary Sources

    Scholarly, professional literature falls under 3 categories, primary, secondary, and tertiary. Published works (also known as a publication) may fall into one or more of these categories, depending on the discipline. See definitions and linked examples of primary, secondary, and tertiary sources. Differences in Publishing Norms by Broader ...

  22. Chapter 9 Methods for Literature Reviews

    Literature reviews can take two major forms. The most prevalent one is the "literature review" or "background" section within a journal paper or a chapter in a graduate thesis. This section synthesizes the extant literature and usually identifies the gaps in knowledge that the empirical study addresses (Sylvester, Tate, & Johnstone, 2013).

  23. Components of the Literature Review

    Literature Review. This is the most time-consuming aspect in the preparation of your research proposal and it is a key component of the research proposal. As described in Chapter 5, the literature review provides the background to your study and demonstrates the significance of the proposed research. Specifically, it is a review and synthesis ...