how to write a literature review in medicine

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Performing a literature review

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A necessary skill for any doctor

What causes disease, which drug is best, does this patient need surgery, and what is the prognosis? Although experience helps in answering these questions, ultimately they are best answered by evidence based medicine. But how do you assess the evidence? As a medical student, and throughout your career as a doctor, critical appraisal of published literature is an important skill to develop and refine. At medical school you will repeatedly appraise published literature and write literature reviews. These activities are commonly part of a special study module, research project for an intercalated degree, or another type of essay based assignment.

Formulating a question

Literature reviews are most commonly performed to help answer a particular question. While you are at medical school, there will usually be some choice regarding the area you are going to review.

Once you have identified a subject area for review, the next step is to formulate a specific research question. This is arguably the most important step because a clear question needs to be defined from the outset, which you aim to answer by doing the review. The clearer the question, the more likely it is that the answer will be clear too. It is important to have discussions with your supervisor when formulating a research question as his or her input will be invaluable. The research question must be objective and concise because it is easier to search through the evidence with a clear question. The question also needs to be feasible. What is the point in having a question for which no published evidence exists? Your supervisor’s input will ensure you are not trying to answer an unrealistic question. Finally, is the research question clinically important? There are many research questions that may be answered, but not all of them will be relevant to clinical practice. The research question we will use as an example to work through in this article is, “What is the evidence for using angiotensin converting enzyme (ACE) inhibitors in patients with hypertension?”

Collecting the evidence

After formulating a specific research question for your literature review, the next step is to collect the evidence. Your supervisor will initially point you in the right direction by highlighting some of the more relevant papers published. Before doing the literature search it is important to agree a list of keywords with your supervisor. A source of useful keywords can be obtained by reading Cochrane reviews or other systematic reviews, such as those published in the BMJ . 1 2 A relevant Cochrane review for our research question on ACE inhibitors in hypertension is that by Heran and colleagues. 3 Appropriate keywords to search for the evidence include the words used in your research question (“angiotensin converting enzyme inhibitor,” “hypertension,” “blood pressure”), details of the types of study you are looking for (“randomised controlled trial,” “case control,” “cohort”), and the specific drugs you are interested in (that is, the various ACE inhibitors such as “ramipril,” “perindopril,” and “lisinopril”).

Once keywords have been agreed it is time to search for the evidence using the various electronic medical databases (such as PubMed, Medline, and EMBASE). PubMed is the largest of these databases and contains online information and tutorials on how to do literature searches with worked examples. Searching the databases and obtaining the articles are usually free of charge through the subscription that your university pays. Early consultation with a medical librarian is important as it will help you perform your literature search in an impartial manner, and librarians can train you to do these searches for yourself.

Literature searches can be broad or tailored to be more specific. With our example, a broad search would entail searching all articles that contain the words “blood pressure” or “ACE inhibitor.” This provides a comprehensive list of all the literature, but there are likely to be thousands of articles to review subsequently (fig 1). ⇓ In contrast, various search restrictions can be applied on the electronic databases to filter out papers that may not be relevant to your review. Figure 2 gives an example of a specific search. ⇓ The search terms used in this case were “angiotensin converting enzyme inhibitor” and “hypertension.” The limits applied to this search were all randomised controlled trials carried out in humans, published in the English language over the last 10 years, with the search terms appearing in the title of the study only. Thus the more specific the search strategy, the more manageable the number of articles to review (fig 3), and this will save you time. ⇓ However, this method risks your not identifying all the evidence in the particular field. Striking a balance between a broad and a specific search strategy is therefore important. This will come with experience and consultation with your supervisor. It is important to note that evidence is continually becoming available on these electronic databases and therefore repeating the same search at a later date can provide new evidence relevant to your review.

Fig 1 Results from a broad literature search using the term “angiotensin converting enzyme inhibitor”

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Fig 2 Example of a specific literature search. The search terms used were “angiotensin converting enzyme inhibitor” and “hypertension.” The limits applied to this search were all randomised controlled trials carried out in humans, published in English over the past 10 years, with the search terms appearing in the title of the study only

Fig 3 Results from a specific literature search (using the search terms and limits from figure 2)

Reading the abstracts (study summary) of the articles identified in your search may help you decide whether the study is applicable for your review—for example, the work may have been carried out using an animal model rather than in humans. After excluding any inappropriate articles, you need to obtain the full articles of studies you have identified. Additional relevant articles that may not have come up in your original search can also be found by searching the reference lists of the articles you have already obtained. Once again, you may find that some articles are still not applicable for your review, and these can also be excluded at this stage. It is important to explain in your final review what criteria you used to exclude articles as well as those criteria used for inclusion.

The National Institute for Health and Clinical Excellence (NICE) publishes evidence based guidelines for the United Kingdom and therefore provides an additional resource for identifying the relevant literature in a particular field. 4 NICE critically appraises the published literature with recommendations for best clinical practice proposed and graded based on the quality of evidence available. Similarly, there are internationally published evidence based guidelines, such as those produced by the European Society of Cardiology and the American College of Chest Physicians, which can be useful when collecting the literature in a particular field. 5 6

Appraising the evidence

Once you have collected the evidence, you need to critically appraise the published material. Box 1 gives definitions of terms you will encounter when reading the literature. A brief guide of how to critically appraise a study is presented; however, it is advisable to consult the references cited for further details.

Box 1: Definitions of common terms in the literature 7

Prospective—collecting data in real time after the study is designed

Retrospective—analysis of data that have already been collected to determine associations between exposure and outcome

Hypothesis—proposed association between exposure and outcome. If presented in the negative it is called the null hypothesis

Variable—a quantity or quality that changes during the study and can be measured

Single blind—subjects are unaware of their treatment, but clinicians are aware

Double blind—both subjects and clinicians are unaware of treatment given

Placebo—a simulated medical intervention, with subjects not receiving the specific intervention or treatment being studied

Outcome measure/endpoint—clinical variable or variables measured in a study subsequently used to make conclusions about the original interventions or treatments administered

Bias—difference between reported results and true results. Many types exist (such as selection, allocation, and reporting biases)

Probability (P) value—number between 0 and 1 providing the likelihood the reported results occurred by chance. A P value of 0.05 means there is a 5% likelihood that the reported result occurred by chance

Confidence intervals—provides a range between two numbers within which one can be certain the results lie. A confidence interval of 95% means one can be 95% certain the actual results lie within the reported range

The study authors should clearly define their research question and ideally the hypothesis to be tested. If the hypothesis is presented in the negative, it is called the null hypothesis. An example of a null hypothesis is smoking does not cause lung cancer. The study is then performed to assess the significance of the exposure (smoking) on outcome (lung cancer).

A major part of the critical appraisal process is to focus on study methodology, with your key task being an assessment of the extent to which a study was susceptible to bias (the discrepancy between the reported results and the true results). It should be clear from the methods what type of study was performed (box 2).

Box 2: Different study types 7

Systematic review/meta-analysis—comprehensive review of published literature using predefined methodology. Meta-analyses combine results from various studies to give numerical data for the overall association between variables

Randomised controlled trial—random allocation of patients to one of two or more groups. Used to test a new drug or procedure

Cohort study—two or more groups followed up over a long period, with one group exposed to a certain agent (drug or environmental agent) and the other not exposed, with various outcomes compared. An example would be following up a group of smokers and a group of non-smokers with the outcome measure being the development of lung cancer

Case-control study—cases (those with a particular outcome) are matched as closely as possible (for age, sex, ethnicity) with controls (those without the particular outcome). Retrospective data analysis is performed to determine any factors associated with developing the particular outcomes

Cross sectional study—looks at a specific group of patients at a single point in time. Effectively a survey. An example is asking a group of people how many of them drink alcohol

Case report—detailed reports concerning single patients. Useful in highlighting adverse drug reactions

There are many different types of bias, which depend on the particular type of study performed, and it is important to look for these biases. Several published checklists are available that provide excellent resources to help you work through the various studies and identify sources of bias. The CONSORT statement (which stands for CONsolidated Standards Of Reporting Trials) provides a minimum set of recommendations for reporting randomised controlled trials and comprises a rigorous 25 item checklist, with variations available for other study types. 8 9 As would be expected, most (17 of 25) of the items focus on questions relating to the methods and results of the randomised trial. The remaining items relate to the title, abstract, introduction, and discussion of the study, in addition to questions on trial registration, protocol, and funding.

Jadad scoring provides a simple and validated system to assess the methodological quality of a randomised clinical trial using three questions. 10 The score ranges from zero to five, with one point given for a “yes” in each of the following questions. (1) Was the study described as randomised? (2) Was the study described as double blind? (3) Were there details of subject withdrawals, exclusions, and dropouts? A further point is given if (1) the method of randomisation was appropriate, and (2) the method of blinding was appropriate.

In addition, the Critical Appraisal Skills Programme provides excellent tools for assessing the evidence in all study types (box 2). 11 The Oxford Centre for Evidence-Based Medicine levels of evidence is yet another useful resource for assessing the methodological quality of all studies. 12

Ensure all patients have been accounted for and any exclusions, for whatever reason, are reported. Knowing the baseline demographic (age, sex, ethnicity) and clinical characteristics of the population is important. Results are usually reported as probability values or confidence intervals (box 1).

This should explain the major study findings, put the results in the context of the published literature, and attempt to account for any variations from previous work. Study limitations and sources of bias should be discussed. Authors’ conclusions should be supported by the study results and not unnecessarily extrapolated. For example, a treatment shown to be effective in animals does not necessarily mean it will work in humans.

The format for writing up the literature review usually consists of an abstract (short structured summary of the review), the introduction or background, methods, results, and discussion with conclusions. There are a number of good examples of how to structure a literature review and these can be used as an outline when writing your review. 13 14

The introduction should identify the specific research question you intend to address and briefly put this into the context of the published literature. As you have now probably realised, the methods used for the review must be clear to the reader and provide the necessary detail for someone to be able to reproduce the search. The search strategy needs to include a list of keywords used, which databases were searched, and the specific search limits or filters applied. Any grading of methodological quality, such as the CONSORT statement or Jadad scoring, must be explained in addition to any study inclusion or exclusion criteria. 6 7 8 The methods also need to include a section on the data collected from each of the studies, the specific outcomes of interest, and any statistical analysis used. The latter point is usually relevant only when performing meta-analyses.

The results section must clearly show the process of filtering down from the articles obtained from the original search to the final studies included in the review—that is, accounting for all excluded studies. A flowchart is usually best to illustrate this. Next should follow a brief description of what was done in the main studies, the number of participants, the relevant results, and any potential sources of bias. It is useful to group similar studies together as it allows comparisons to be made by the reader and saves repetition in your write-up. Boxes and figures should be used appropriately to illustrate important findings from the various studies.

Finally, in the discussion you need to consider the study findings in light of the methodological quality—that is, the extent of potential bias in each study that may have affected the study results. Using the evidence, you need to make conclusions in your review, and highlight any important gaps in the evidence base, which need to be dealt with in future studies. Working through drafts of the literature review with your supervisor will help refine your critical appraisal skills and the ability to present information concisely in a structured review article. Remember, if the work is good it may get published.

Originally published as: Student BMJ 2012;20:e404

Competing interests: None declared.

Provenance and peer review: Not commissioned; externally peer reviewed.

• ↵ The Cochrane Library. www3.interscience.wiley.com/cgibin/mrwhome/106568753/HOME?CRETRY=1&SRETRY=0 .
• ↵ British Medical Journal . www.bmj.com/ .
• ↵ Heran BS, Wong MMY, Heran IK, Wright JM. Blood pressure lowering efficacy of angiotensin converting enzyme (ACE) inhibitors for primary hypertension. Cochrane Database Syst Rev 2008 ; 4 : CD003823 , doi: 10.1002/14651858.CD003823.pub2. OpenUrl PubMed
• ↵ National Institute for Health and Clinical Excellence. www.nice.org.uk .
• ↵ European Society of Cardiology. www.escardio.org/guidelines .
• ↵ Geerts WH, Bergqvist D, Pineo GF, Heit JA, Samama CM, Lassen MR, et al. Prevention of venous thromboembolism: American College of Chest Physicians evidence-based clinical practice guidelines (8th ed). Chest 2008 ; 133 : 381 -453S. OpenUrl CrossRef
• ↵ Wikipedia. http://en.wikipedia.org/wiki .
• ↵ Moher D, Schulz KF, Altman DG, Egger M, Davidoff F, Elbourne D, et al. The CONSORT statement: revised recommendations for improving the quality of reports of parallel-group randomised trials. Lancet 2001 ; 357 : 1191 -4. OpenUrl CrossRef PubMed Web of Science
• ↵ The CONSORT statement. www.consort-statement.org/ .
• ↵ Jadad AR, Moore RA, Carroll D, Jenkinson C, Reynolds DJ, Gavaghan DJ, et al. Assessing the quality of reports of randomized clinical trials: is blinding necessary? Control Clin Trials 1996 ; 17 : 1 -12. OpenUrl CrossRef PubMed Web of Science
• ↵ Critical Appraisal Skills Programme (CASP). www.sph.nhs.uk/what-we-do/public-health-workforce/resources/critical-appraisals-skills-programme .
• ↵ Oxford Centre for Evidence-based Medicine—Levels of Evidence. www.cebm.net .
• ↵ Van den Bruel A, Thompson MJ, Haj-Hassan T, Stevens R, Moll H, Lakhanpaul M, et al . Diagnostic value of laboratory tests in identifying serious infections in febrile children: systematic review. BMJ 2011 ; 342 : d3082 . OpenUrl Abstract / FREE Full Text
• ↵ Awopetu AI, Moxey P, Hinchliffe RJ, Jones KG, Thompson MM, Holt PJ. Systematic review and meta-analysis of the relationship between hospital volume and outcome for lower limb arterial surgery. Br J Surg 2010 ; 97 : 797 -803. OpenUrl CrossRef PubMed

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• The Pandora's Box of Evidence Synthesis and the case for a living Evidence Synthesis Taxonomy | BMJ Evidence-Based Medicine, 2023
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• A typology of reviews: an analysis of 14 review types and associated methodologies | Health Information and Libraries Journal, 2009
• Conceptual recommendations for selecting the most appropriate knowledge synthesis method to answer research questions related to complex evidence | Journal of Clinical Epidemiology, 2016
• Methods for knowledge synthesis: an overview | Heart & Lung: The Journal of Critical Care, 2014
• Not sure what type of review to conduct? Brief descriptions of each type plus tools to help you decide

• Ten simple rules for writing a literature review | PLoS Computational Biology, 2013
• The Purpose, Process, and Methods of Writing a Literature Review | AORN Journal. 2016
• Why, When, Who, What, How, and Where for Trainees Writing Literature Review Articles. | Annals of Biomed Engineering, 2019
• So You Want to Write a Narrative Review Article? | Journal of Cardiothoracic and Anesthesia, 2021
• An Introduction to Writing Narrative and Systematic Reviews - Tasks, Tips and Traps for Aspiring Authors | Heart, Lung, and Circulation, 2018

• The Literature Review: A Foundation for High-Quality Medical Education Research | Journal of Graduate Medical Education, 2016
• Writing an effective literature review : Part I: Mapping the gap | Perspectives on Medical Education, 2018
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A Step-by-Step Guide to Writing a Scientific Review Article

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Manisha Bahl, A Step-by-Step Guide to Writing a Scientific Review Article, Journal of Breast Imaging , Volume 5, Issue 4, July/August 2023, Pages 480–485, https://doi.org/10.1093/jbi/wbad028

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Scientific review articles are comprehensive, focused reviews of the scientific literature written by subject matter experts. The task of writing a scientific review article can seem overwhelming; however, it can be managed by using an organized approach and devoting sufficient time to the process. The process involves selecting a topic about which the authors are knowledgeable and enthusiastic, conducting a literature search and critical analysis of the literature, and writing the article, which is composed of an abstract, introduction, body, and conclusion, with accompanying tables and figures. This article, which focuses on the narrative or traditional literature review, is intended to serve as a guide with practical steps for new writers. Tips for success are also discussed, including selecting a focused topic, maintaining objectivity and balance while writing, avoiding tedious data presentation in a laundry list format, moving from descriptions of the literature to critical analysis, avoiding simplistic conclusions, and budgeting time for the overall process.

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Writing in the Health Sciences: Research and Lit Reviews

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What Is a Literature Review?

In simple terms, a literature review investigates the available information on a certain topic. It may be only a knowledge survey with an intentional focus. However, it is often a well-organized examination of the existing research which evaluates each resource in a systematic way. Often a lit review will involve a series of inclusion/exclusion criteria or an assessment rubric which examines the research in-depth. Below are some interesting sources to consider.

The Writing Center's Literature Reviews - UNC-Chapel Hill's writing center explains some of the key criteria involved in doing a literature review.

Literature Review vs. Systematic Review - This recent article details the difference between a literature review and a systematic review. Though the two share similar attributes, key differences are identified here.

Literature Review Steps

1. Identify a research question. For example: "Does the use of warfarin in elderly patients recovering from myocardial infarction help prevent stroke?"

2. Consider which databases might provide information for your topic. Often PubMed or CINAHL will cover a wide spectrum of biomedical issues. However, other databases and grey literature sources may specialize in certain disciplines. Embase is generally comprehensive but also specializes in pharmacological interventions.

3. Select the major subjects or ideas from your question.  Focus in on the particular concepts involved in your research. Then brainstorm synonyms and related terminology for these topics.

4. Look for the  preferred indexing terms for each concept in your question. This is especially important with databases such as PubMed, CINAHL, or Scopus where headings within the MeSH database or under the Emtree umbrella are present.  For example, the above question's keywords such as " warfarin " or "myocardial infarction" can involve related terminology or subject headings such as "anti-coagulants" or "cardiovascular disease."

5. Build your search using boolean operators. Combine the synonyms in your database using boolean operators such as AND or OR. Sometimes it is necessary to research parts of a question rather than the whole. So you might link searches for things like the preventive effects of anti-coagulants with stroke or embolism, then AND these results with the therapy for patients with cardiovascular disease.

6. Filter and save your search results from the first database (do this for all databases). This may be a short list because of your topic's limitations, but it should be no longer than 15 articles for an initial search. Make sure your list is saved or archived and presents you with what's needed to access the full text.

7. Use the same process with the next databases on your list. But pay attention to how certain major headings may alter the terminology. "Stroke" may have a suggested term of "embolism" or even "cerebrovascular incident" depending on the database.

8. Read through the material for inclusion/exclusion . Based on your project's criteria and objective, consider which studies or reviews deserve to be included and which should be discarded. Make sure the information you have permits you to go forward. 

9. Write the literature review. Begin by summarizing why your research is important and explain why your approach will help fill gaps in current knowledge. Then incorporate how the information you've selected will help you to do this. You do not need to write about all of the included research you've chosen, only the most pe rtinent.

10. Select the most relevant literature for inclusion in the body of your report. Choose the articles and data sets that are most particularly relevant to your experimental approach. Consider how you might arrange these sources in the body of your draft. 

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Call #: WZ 345 G192h 2011

ISBN #: 9780763771867

This book details a practical, step-by-step method for conducting a literature review in the health sciences. Aiming to  synthesize the information while also analyzing it, the Matrix Indexing System enables users to establish a  structured process for tracking, organizing and integrating the knowledge within a collection.

Key Research Databases

PubMed -  The premier medical database for review articles in medicine, nursing, healthcare, other related biomedical disciplines. PubMed contains over 20 million citations and can be navigated through multiple database capabilities and searching strategies.

CINAHL Ultimate - Offers comprehensive coverage of health science literature. CINAHL is particularly useful for those researching the allied disciplines of nursing, medicine, and pharmaceutical sciences.

Scopus - Database with over 12 million abstracts and citations which include peer-reviewed titles from international and Open Access journals. Also includes interactive bibliometrics and researcher profiling.

Embase - Elsevier's fully interoperable database of both Medline and Emtree-indexed articles. Embase also specializes in pharmacologic interventions.

Cochrane - Selected evidence-based medicine resources from the Cochrane Collaboration that includes peer-reviewed systematic reviews and randomized controlled trials. Access this database through OVID with TTUHSC Libraries.

DARE - Literally the Datatase of Abstracts of Reviews of Effectiveness, this collection of systematic reviews and other evidence-based research contains critical assessments from a wide variety of medical journals.

TRIP - This TRIP database is structured according to the level of evidence for its EBM content. It allows users to quickly and easily locate high-quality, accredited medical literature for clinical and research purposes.

Web of Science - Contains bibliographic articles and data from a wide variety of publications in the life sciences and other fields. Also, see this link for conducting a lit review exclusively within Web of Science.

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How to Conduct a Literature Review (Health Sciences and Beyond)

What is a literature review, traditional (narrative) literature review, integrative literature review, systematic reviews, meta-analysis, scoping review.

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• Systematic Reviews by Roy Brown Last Updated Oct 17, 2023 559 views this year
• Write a Literature Review by John Glover Last Updated Oct 16, 2023 2948 views this year

A literature review provides an overview of what's been written about a specific topic. There are many different types of literature reviews. They vary in terms of comprehensiveness, types of study included, and purpose. 

The other pages in this guide will cover some basic steps to consider when conducting a traditional health sciences literature review. See below for a quick look at some of the more popular types of literature reviews.

For additional information on a variety of review methods, the following article provides an excellent overview.

Grant MJ, Booth A. A typology of reviews: an analysis of 14 review types and associated methodologies. Health Info Libr J. 2009 Jun;26(2):91-108. doi: 10.1111/j.1471-1842.2009.00848.x. Review. PubMed PMID: 19490148.

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Home » Office of Curriculum » Medical Student Scholarship » III Scholarship Start Here » Scholarship of Integration » Key Steps in a Literature Review

Key Steps in a Literature Review

The 5 key steps  below are most relevant to narrative reviews. Systematic reviews include the additional step of using a standardized scoring system to assess the quality of each article. More information on  Step 1 can be found  here  and Step 5  here .

• Consider the purpose and rationale of a review
• Clearly articulate the components of the question
• The research question and purpose of your review should guide the development of your search strategy (i.e. which databases to search and which search terms to use)
• Justify any limitations you create for your search,
• Determine inclusion and exclusion criteria.
• Start by reviewing abstracts for relevant articles. Once this is complete, then begin a full text review of the remaining articles.
• Develop a data-charting form to extract data from each article. Update this form as needed if you find there is more information worth collecting.
• The resulting forms will serve as a summary of each article that will facilitate the process of synthesizing your results (i.e. the selected articles).
• In your analysis, include a numerical summary of studies included, an evidence table summarizing included articles, and a qualitative summary of the results.
• Report the results in the context of the overall purpose or research question.
• Consider the meaning of your results. Discuss limitations and implications for future research, practice, and/or policy.

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Searching the public health & medical literature more effectively: literature review help.

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Literature Review Tips Handouts

Write about something you are passionate about!

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Ten simple rules for writing a literature review . Pautasso M. PLoS Comput Biol. 2013;9(7):e1003149. doi:10.1371/journal.pcbi.1003149

Conducting the Literature Search . Chapter 4 of Chasan-Taber L. Writing Dissertation and Grant Proposals: Epidemiology, Preventive Medicine and Biostatistics. New York: Chapman and Hall/CRC, 2014.

A step-by-step guide to writing a research paper, from idea to full manuscript . Excellent and easy to follow blog post by Dr. Raul Pacheco-Vega.

Data Extraction

Data extraction answers the question “what do the studies tell us?”

At a minimum, consider the following when extracting data from the studies you are reviewing ( source ):

• Only use the data elements relevant to your question;
• Use a table, form, or tool (such as Covidence ) for data extraction;
• Test your methods and tool for missing data elements, redundancy, consistency, clarity.

Here is a table of data elements to consider for your data extraction. (From University of York, Centre for Reviews and Dissemination).

Critical Reading

As you read articles, write notes. You may wish to create a table, answering these questions:

• What is the hypothesis?
• What is the method? Rigorous? Appropriate sample size? Results support conclusions?
• What are the key findings?
• How does this paper support/contradict other work?
• How does it support/contradict your own approach?
• How significant is this research? What is its special contribution?
• Is this research repeating existing approaches or making a new contribution?
• What are its strengths?
• What are its weaknesses/limitations?

From: Kearns, H. & Finn, J. (2017) Supervising PhD Students: A Practical Guide and Toolkit . AU: Thinkwell, p. 103.

Submitting to a Journal? First Identify Journals That Publish on Your Topic

Through Scopus

• Visit the  Scopus database.
• Search for recent articles on your research topic.
• Above the results, click “Analyze search results."
• Click in the "Documents per year by source" box.
• On the left you will see the results listed by the number of articles published on your research topic per journal.

Through Web of Science

• Visit the Web of Science database.
• In the results, click "Analyze Results" on the right hand side.
• From the drop-down menu near the top left, choose "Publication Titles."
• Change the "Minimum record count (threshold)," if desired.
• Scroll down for a table of results by journal title.
• JANE (Journal/Author Name Estimator) Use JANE to help you discover and decide where to publish an article you have authored. Jane matches the abstract of your article to the articles in Medline to find the best matching journals (or authors, or articles).
• Jot (Journal Targeter) Jot uses Jane and other data to determine journals likely to publish your article (based on title, abstract, references) against the impact metric of those journals. From Yale University.
• EndNote Manuscript Matcher Using algorithms and data from the Web of Science and Journal Citation Reports, Manuscript Matcher identifies the most relevant and impactful journals to which one may wish to submit a manuscript. Access Manuscript Matcher via EndNote X9 or EndNote 20.
• DOAJ (Directory of Open Access Journals) Journal Lookup Look up a journal title on DOAJ and find information on publication fees, aims and scope, instructions for authors, submission to publication time, copyright, and more.

Writing Help @UCB

Here is a short list of sources of writing help available to UC Berkeley students, staff, and faculty:

• Purdue OWL Excellent collection of guides on writing, including citing/attribution, citation styles, grammar and punctuation, academic writing, and much more.
• Berkeley Writing: College Writing Programs "Our philosophy includes small class size, careful attention to building your critical reading and thinking skills along with your writing, personalized attention, and a great deal of practice writing and revising." Website has a Writing Resources Database .
• Graduate Writing Center, Berkeley Graduate Division Assists graduate students in the development of academic skills necessary to successfully complete their programs and prepare for future positions. Workshops and online consultations are offered on topics such as academic writing, grant writing, dissertation writing , thesis writing , editing, and preparing articles for publication, in addition to writing groups and individual consultations.
• Nature Masterclass on Scientific Writing and Publishing For Postdocs, Visiting Scholars, and Visiting Student Researchers with active, approved appointments, and current UC Berkeley graduate students who are new to publishing or wish to refresh their skills. Part 1: Writing a Research Paper; Part 2: Publishing a Research Paper; Part 3: Writing and Publishing a Review Paper. Offered by Visiting Researcher Scholar and Postdoc Affairs (VSPA) program; complete this form to gain access.

Alternative Publishing Formats

Here is some information and tips on getting your research to a broader, or to a specialized, audience

• Creating One-Page Reports One-page reports are a great way to provide a snapshot of a project’s activities and impact to stakeholders. Summarizing key facts in a format that is easily and quickly digestible engages the busy reader and can make your project stand out. From EvaluATE .
• How to write an Op-ed (Webinar) Strategies on how to write sharp op-eds for broader consumption, one of the most important ways to ensure your analysis and research is shared in the public sphere. From the Institute for Research on Public Policy .
• 10 tips for commentary writers From UC Berkeley Media Relations’ 2017 Op-Ed writing workshop.
• Journal of Science Policy and Governance JSPG publishes policy memos, op-eds, position papers, and similar items created by students.
• Writing Persuasive Policy Briefs Presentation slides from a UCB Science Policy Group session.
• 3 Essential Steps to Share Research With Popular Audiences (Inside Higher Ed) How to broaden the reach and increase the impact of your academic writing. Popular writing isn’t a distraction from core research!

The Politics of Citation

"One of the feminist practices key to my teaching and research is a feminist practice of citation."

From The Digital Feminist Collective , this blog post emphasizes the power of citing.

"Acknowledging and establishing feminist genealogies is part of the work of producing more just forms of knowledge and intellectual practice."

Here's an exercise (docx) to help you in determining how inclusive you are when citing.

Additional Resources for Inclusive Citation Practices :

• BIPOC Scientists Citation guide (Rockefeller Univ.).
• Conducting Research through an Anti-Racism Lens (Univ. of Minnesota Libraries).
• cleanBib (Code to probabilistically assign gender and race proportions of first/last authors pairs in bibliography entries).
• Balanced Citer (Python script guesses the race and gender of the first and last authors for papers in your citation list and compares your list to expected distributions based on a model that accounts for paper characteristics).
• Read Black women's work;
• Integrate Black women into the CORE of your syllabus (in life & in the classroom);
• Acknowledge Black women's intellectual production;
• Make space for Black women to speak;
• Give Black women the space and time to breathe.
• CiteASista .
• << Previous: Organize Citations & Search Strategies
• Next: Need More Help? >>
• Last Updated: May 22, 2024 3:44 PM
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Medicine Guide: Literature Reviews

• Getting Started
• Use the Library This link opens in a new window
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• Search for Resources This link opens in a new window
• Evaluate What I Find This link opens in a new window
• Avoid Plagiarism This link opens in a new window
• Drug Databases
• Articles, books, & more
• Search Smarter This link opens in a new window
• Referencing This link opens in a new window
• Measuring Research Impact This link opens in a new window
• Publishing Academic Research This link opens in a new window
• Resources for Working With Data
• Resources for Writing a Thesis
• Literature Reviews
• Finding Statistics
• Working in Groups
• Using Reference Materials

Writing the Literature Review (Part 1)

Writing the Literature Review (Part 2)

Writing a literature review

Your Liaison Librarian will be able to provide support and advice when you are doing your literature review, so make an appointment with your librarian when you start your research.

• Liaison Librarians
• Literature review template
• The Literature Review Library Guide

Literature review books @ JCU Library

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• Last Updated: Apr 26, 2024 10:38 AM
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How to conduct a literature review

The purpose of literature reviews and how to execute them.

Agencja Fotograficzna Caro / Alamy Stock Photo

In recent decades, the ‘evidence-based medicine’ movement has become widely accepted and, consequently, decisions regarding what is best practice are informed by the best available evidence [1] . However, an ever-increasing quantity of evidence published in literature has meant that healthcare providers, researchers, and policy makers are inundated with unmanageable amounts of information, which can hinder, rather than inform, rational decision making [2] . It is therefore vital that healthcare professionals, including pharmacists, appreciate the importance of evaluating the available evidence when attempting to answer a clinical question [3] . A literature review can therefore be considered “the comprehensive study and interpretation of literature that relates to a particular topic” [4] .

When conducted correctly, a literature review can be viewed as more than simply a cursory overview of the literature on a given topic. Indeed, they are often viewed as a piece of research in their own right. A historical example of the value of literature reviews in informing evidence-based practice is that of streptokinase in the treatment of myocardial infarction (MI). In the 1970s, 33 separate clinical trials comparing streptokinase with a placebo for the treatment of MI had been conducted and their results published. Individually, these trials provided inconclusive evidence regarding the role of streptokinase. However, a re-analysis of their combined results clearly demonstrated the beneficial effect of streptokinase. As a result the medicine became part of the standard treatment following MI, thereby transforming care and saving lives [2] .

Narrative versus systematic literature reviews

Literature reviews can be broadly divided into narrative (descriptive) reviews and systematic reviews [5] . The most important difference between the two categories of reviews is the difference in their level of associated scientific rigour. Narrative literature reviews provide an overview of the literature, typically from the perspective of an ‘expert in the field’ [1] . Such reviews often report findings in a format that includes a brief summary of each included study. While such reviews can be informative, particularly when there has been no previous attempt to assimilate the literature in a given area, narrative reviews are often criticised as having a high risk of various types of bias associated with them [6] . Narrative reviews typically rely on subjective and non-systematic methods of selecting and reviewing data. Consequently, authors may intentionally or unintentionally cite only those literature sources that reinforce the author’s preconceived hypotheses or promote their own views on a topic [7] .

In contrast to a narrative review, a systematic literature review aims to identify all the available evidence on a topic and appraise the quality of that evidence [4] . Therefore, such reviews have the ability to either answer the research question or, failing that, identify gaps in the existing literature which highlight the need for further high quality research into a specific area [8] . Established in 1993, the Cochrane collaboration is an international organisation that produces systematic reviews, often regarded as the gold standard of evidence, concerning the effectiveness of healthcare interventions.

The purpose of a literature review

Literature reviews may be conducted for a variety of reasons, for example, to form part of a research proposal or introductory section in an academic paper, or to inform evidence-based practice [8] . The original focus of evidence-based medicine concerned mainly clinical research questions, such as the streptokinase example. However, increasingly, more research is being conducted in the area of health services research, which incorporates social science perspectives with the contribution of individuals and institutions that deliver care. Pharmacy practice research (a sub-type of health services research) is concerned with investigating how and why people access pharmacy services, new roles for pharmacists, and outcomes for patients as a result of pharmacy services [9] . Whether conducting either a clinical pharmacy or a pharmacy practice literature review, the following basic principles outlined in this article should be followed.

Searching with a strategy

While time and resource constraints may not allow for a definitive systematic review to be conducted, those attempting to undertake a literature review should nevertheless adopt a ‘systematic approach’ [10] . The first step in any literature review is to define the research question (i.e. the scope of the review). This will inform which studies or other forms of evidence are to be included and excluded from the literature review.

Questions that should be asked at this stage include:

• Which study designs are relevant to the review? For example, double-blind randomised controlled trials, observational studies or qualitative research.
• Is there a particular population of interest? For example, paediatrics, pregnant women or people living in care homes.
• Are there particular outcomes of interest? For example, mortality, costs or quality of life.

The literature search strategy is a fundamental component of any literature review, because errors in the search process could produce an incomplete and therefore biased evidence base for the review. Where possible, reviewers should consult with a pharmacy or healthcare librarian who can assist in developing and refining an appropriate search strategy [11] . The search should be conducted in more than one electronic database to help ensure all relevant papers are identified. The main medical literature databases are Medline and Embase. International Pharmaceutical Abstracts (IPA) is also an important database to consider because it indexes many pharmacy-specific journals not found in the larger databases. It should also be remembered that pharmacy literature often overlaps with other disciplines therefore consideration should be given to databases such as the Cumulative Index of Nursing and Allied Health (CINAHL), as well as condition-specific databases, for example PsycInfo.

When conducting searches on electronic databases, thought must be given to the search terms used. Several keywords can exist for each search term and all should be included in the search (e.g. older adult/elderly/aged, are all terms that could be used synonymously). Most databases also have the facility to identify all possible endings of the key terms; this is usually denoted with an asterisk. For example, by searching for ‘pharm*’, articles containing any of the following would be retrieved: pharmacist, pharmacists, pharmacy, pharmaceutical. Boolean operators (e.g. ‘and’, ‘or’, ‘not’) can also be used to combine search terms to refine the search results [12] .

Avoiding publication bias

It has been well documented that studies that report significant results are more likely than those reporting non-significant results to be published, cited by others and produce multiple publications, introducing what is known as ‘publication bias’. Consequently, such studies are also more likely to be identified and included in systematic reviews [13] .

For this reason, efforts should be made to identify all relevant literature on the review topic so the search should not be limited solely to electronic databases [14] . Additional search strategies include hand-checking relevant article reference lists and personal communication with experts in the field. Searching the ‘grey literature’ is of particular importance for pharmacy practice literature reviews because relevant articles written by non-academic pharmacists are often not published in traditional academic journals [15] .

The importance of such additional search strategies cannot be underestimated. Greenhalgh and Peacock reported that, in a literature review concerning innovations in healthcare organisations, 51% of the sources included in the eventual review were identified by hand-searching reference lists, while an additional 24% were identified through personal communications [7] . The search strategy, including databases searched, all search terms used, the limits of the search (for example, written in the English language, published in the last decade), the number of results retrieved from each resource and the date the search was conducted should be carefully documented. Although it can never be guaranteed that the entirety of relevant literature will be identified, conducting the search in a systematic manner will help avoid omissions, and where they do exist they can be said to be unintentional [9] .

Once the search has been performed, the next step is to screen the titles or abstracts (or both) of the identified articles against the predefined inclusion and exclusion criteria. If the article cannot be excluded on the basis of the information contained in the abstract, efforts must be made to access the full paper in order to reach a decision. Conducting a literature review can be a time-consuming process and the time taken to complete is directly related to number of citations identified by the initial search. Allen et al . [16] calculated that it would take a reviewer more than 1,000 hours to complete a literature review involving the screening of 2,500 articles. For this reason, it is worth considering the use of free citation management software, such as Refworks, Mendeley and Endnote, which can be used to manage references retrieved from the literature search.

Drawing conclusions

Studies identified as part of a literature review may report contradictory findings and the quality of the individual studies will have a direct impact on the overall findings of the literature review. When assimilating the evidence identified, the reviewer should attempt to assess the quality of the evidence provided by the individual studies to arrive at valid conclusions [6] . It is recommended that when conducting a literature review, the author should make a judgement of the quality of the evidence provided within the included studies or articles using appropriate assessment guidelines [17] . For example, the Cochrane Collaboration’s risk-of-bias tool attempts to aid quality assessment in terms of assessing potential sources of bias in studies.

In an effort to draw quantitative conclusions within a systematic review, data from individual studies may be pooled quantitatively and reanalysed. A meta-analysis is a statistical method used to combine the outcomes of individual studies to produce data with more power than the individual studies. By pooling the results of individual studies, the sample size is effectively increased, thereby increasing the statistical power of the analysis, which in turns narrows the confidence interval around the effect size, with the result that the overall estimate of effect is more robust [9] . Individual studies included in the analysis are assigned weights, with greater weight assigned to studies with larger sample sizes. The results of a meta-analysis are often displayed graphically in what is known as a “forest plot” [18] .

Publishing your literature review

Targeting an appropriate journal.

• Ensure the scope of your review aligns with the scope of the journal. Familiarise yourself with the journal’s mission statement and the typical content of the journal.
• Be aware of the journal’s target audience in relation to the scope of the review (e.g. does the journal have a pharmacy-specific or multidisciplinary audience? Does the journal have a national or international readership?)
• Consider whether the journal offers open-access publishing. Increasingly, funding bodies stipulate that articles are published only in open-access journals.
• Look at the journal’s impact factor. While articles published in journals with higher impact factors tend to get cited more, high-impact journals have lower article acceptance rates, making it potentially more challenging to get your review published.

Submitting the manuscript

• Familiarise yourself with the journal’s ‘guidelines for authors’. These will dictate the accepted word limit of a review in addition to other formatting and submission stipulations surrounding tables, figures and references, etc.
• Write a cover letter, addressed to the editor of the journal, to accompany your manuscript submission. The cover letter should highlight why the review is important and why you think it is a good fit for the chosen journal. 

Reading this article counts towards your CPD

You can use the following forms to record your learning and action points from this article from Pharmaceutical Journal Publications.

Your CPD module results are stored against your account here at The Pharmaceutical Journal . You must be registered and logged into the site to do this. To review your module results, go to the ‘My Account’ tab and then ‘My CPD’.

Any training, learning or development activities that you undertake for CPD can also be recorded as evidence as part of your RPS Faculty practice-based portfolio when preparing for Faculty membership. To start your RPS Faculty journey today, access the portfolio and tools at www.rpharms.com/Faculty

If your learning was planned in advance, please click:

If your learning was spontaneous, please click:

[1] Akobeng AK. Understanding systematic reviews and meta-analysis. Arch Dis Child 2005;90:845–848. doi: 10.1136/adc.2004.058230

[2] Mulrow CD. Systematic Reviews: Rationale for systematic reviews. The BMJ 1994;309:597. doi: 10.1136/bmj.309.6954.597

[3] Guyatt G, Cairns J, Churchill D et al . Evidence-based medicine: a new approach to teaching the practice of medicine. JAMA 1992;268:2420–2425. doi: 10.1001/jama.268.17.2420

[4] Aveyard H. Doing a literature review in health and social care: a practical guide. 3rd Edn. Open University Press 2014. doi: 10.7748/ns.29.27.30.s33

[5] Grant MJ & Booth A. A typology of reviews: an analysis of 14 review types and associated methodologies. Health Info Libr J 2009;26:91–108. doi: 10.1111/j.1471-1842.2009.00848.x

[6] Green BN. Writing narrative literature reviews for peer-reviewed journals: secrets of the trade. J Chiropr Med 2006;5:101–117. doi: 10.1016/S0899-3467(07)60142-6

[7] Greenhalgh T & Peacock R. Effectiveness and efficiency of search methods in systematic reviews of complex evidence: audit of primary sources. The BMJ . 2005;331:1064–1065. doi: 10.1136/bmj.38636.593461.68

[8] Jesson J & Lacey F. How to do (or not to do) a critical literature review. Pharmacy Education 2006;6:139–148. doi: 10.1080/15602210600616218

[9] Babar Z. Pharmacy Practice Research Methods: Adis/Springer International Publishing, Switzerland, 2015.

[10] McKee M & Britton A. Conducting a literature review on the effectiveness of health care interventions. Health Policy Plan 1997;12:262–267. doi: 10.1093/heapol/12.3.262

[11] McGowan J & Sampson M. Systematic reviews need systematic searchers. J Med Libr Assoc 2005;93:74–80.

[12] Cronin P, Ryan F & Coughlan M. Undertaking a literature review: a step-by-step approach. BJN 2008;17:38–43.  doi: 10.12968/bjon.2008.17.1.28 059

[13] Sterne J, Egger M & Smith GD. Investigating and dealing with publication and other biases in meta-analysis. The BMJ 2001;323:101. doi: 10.1136/bmj.323.7304.101

[14] Crumley ET, Wiebe N, Cramer K et al . Which resources should be used to identify RCT/CCTs for systematic reviews: a systematic review. BMC Med Res Methodol 2005;5:24. doi: 10.1186/1471-2288-5-24

[15] Charrois T, Durec T & Tsuyuki R. Systematic reviews of pharmacy practice research: methodologic issues in searching, evaluating, interpreting, and disseminating results. Ann Pharmacother  2009;43:118–122. doi: 10.1345/aph.1l302

[16] Allen E & Olkin I. Estimating time to conduct a meta-analysis from number of citations retrieved. JAMA 1999;282:634–635. PMID: 10517715

[17] Jüni P, Altman DG & Egger M. Assessing the quality of controlled clinical trials. The BMJ 2001;323:42–46. doi: 10.1136/bmj.323.7303.42

[18] Lewis S & Clarke M. Forest plots: trying to see the wood and the trees. The BMJ 2001;322:1479–1480. doi: 10.1136/bmj.322.7300.1479

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What is a literature review?

Systematic reviews vs literature reviews, literature reviews - articles, writing literature reviews, frequently used journal article databases.

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The literature review is the qualitative summary of evidence on a topic using informal or subjective methods to collect and interpret studies.The literature review can inform a particular research project or can result in a review article publication.

• Aaron L. Writing a literature review article. Radiol Technol. 2008 Nov-Dec; 80(12): 185-6.
• Gasparyan AY, Ayvazyan L, Blackmore H, Kitas GD. Writing a narrative biomedical review: considerations for authors, peer reviewers, and editors. Rheumatol Int. 2011 Nov; 31(11): 1409-17.
• Matharu GS, Buckley CD. Performing a literature review: a necessary skill for any doctor. Student BMJ. 2012; 20:e404. Requires FREE site registration
• Literature Reviews The Writing Center at University of North Carolina at Chapel Hill has created a succinct handout that explains what a literature review is and offer insights into the form and construction of a literature review in the humanities, social sciences, and sciences.
• Review Articles (Health Sciences) Guide Identifies the difference between a systematic review and a literature review. Connects to tools for research, writing, and publishing.

• Systematic Approaches to a Successful Literature Review by Andrew Booth; Diana Papaioannou; Anthea Sutton Call Number: Norris Medical Library, Upper Level, LB 1047.3 B725s 2012
• Documenting your search This resource provides guidance on how to document and save database search strategies.
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• Ulrich's -- One More Way To Find Peer-reviewed Papers

"Literature review," "systematic literature review," "integrative literature review" -- these are terms used in different disciplines for basically the same thing -- a rigorous examination of the scholarly literature about a topic (at different levels of rigor, and with some different emphases).  

1. Our library's guide to Writing a Literature Review

2. Other helpful sites

• Writing Center at UNC (Chapel Hill) -- A very good guide about lit reviews and how to write them
• Literature Review: Synthesizing Multiple Sources (LSU, June 2011 but good; PDF) -- Planning, writing, and tips for revising your paper

3. Welch Library's list of the types of expert reviews

Doing a good job of organizing your information makes writing about it a lot easier.

You can organize your sources using a citation manager, such as refworks , or use a matrix (if you only have a few references):.

• Use Google Sheets, Word, Excel, or whatever you prefer to create a table
• The column headings should include the citation information, and the main points that you want to track, as shown

Synthesizing your information is not just summarizing it. Here are processes and examples about how to combine your sources into a good piece of writing:

• Purdue OWL's Synthesizing Sources
• Synthesizing Sources (California State University, Northridge)

Annotated Bibliography  

An "annotation" is a note or comment. An "annotated bibliography" is a "list of citations to books, articles, and [other items]. Each citation is followed by a brief...descriptive and evaluative paragraph, [whose purpose is] to inform the reader of the relevance, accuracy, and quality of the sources cited."*

• Sage Research Methods (database) --> Empirical Research and Writing (ebook) -- Chapter 3: Doing Pre-research  
• Purdue's OWL (Online Writing Lab) includes definitions and samples of annotations  
• Cornell's guide * to writing annotated bibliographies  

* Thank you to Olin Library Reference, Research & Learning Services, Cornell University Library, Ithaca, NY, USA https://guides.library.cornell.edu/annotatedbibliography

What does "peer-reviewed" mean?

• If an article has been peer-reviewed before being published, it means that the article has been read by other people in the same field of study ("peers").
• The author's reviewers have commented on the article, not only noting typos and possible errors, but also giving a judgment about whether or not the article should be published by the journal to which it was submitted.

How do I find "peer-reviewed" materials?

• Most of the the research articles in scholarly journals are peer-reviewed.
• Many databases allow you to check a box that says "peer-reviewed," or to see which results in your list of results are from peer-reviewed sources. Some of the databases that provide this are Academic Search Ultimate, CINAHL, PsycINFO, and Sociological Abstracts.

What kinds of materials are *not* peer-reviewed?

• open web pages
• most newspapers, newsletters, and news items in journals
• letters to the editor
• press releases
• columns and blogs
• book reviews
• anything in a popular magazine (e.g., Time, Newsweek, Glamour, Men's Health)

If a piece of information wasn't peer-reviewed, does that mean that I can't trust it at all?

No; sometimes you can. For example, the preprints submitted to well-known sites such as  arXiv  (mainly covering physics) and  CiteSeerX (mainly covering computer science) are probably trustworthy, as are the databases and web pages produced by entities such as the National Library of Medicine, the Smithsonian Institution, and the American Cancer Society.

Is this paper peer-reviewed? Ulrichsweb will tell you.

1) On the library home page , choose "Articles and Databases" --> "Databases" --> Ulrichsweb

2) Put in the title of the JOURNAL (not the article), in quotation marks so all the words are next to each other

3) Mouse over the black icon, and you'll see that it means "refereed" (which means peer-reviewed, because it's been looked at by referees or reviewers). This journal is not peer-reviewed, because none of the formats have a black icon next to it:

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How to write a good scientific review article

Affiliation.

• 1 The FEBS Journal Editorial Office, Cambridge, UK.
• PMID: 35792782
• DOI: 10.1111/febs.16565

Literature reviews are valuable resources for the scientific community. With research accelerating at an unprecedented speed in recent years and more and more original papers being published, review articles have become increasingly important as a means to keep up to date with developments in a particular area of research. A good review article provides readers with an in-depth understanding of a field and highlights key gaps and challenges to address with future research. Writing a review article also helps to expand the writer's knowledge of their specialist area and to develop their analytical and communication skills, amongst other benefits. Thus, the importance of building review-writing into a scientific career cannot be overstated. In this instalment of The FEBS Journal's Words of Advice series, I provide detailed guidance on planning and writing an informative and engaging literature review.

© 2022 Federation of European Biochemical Societies.

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Literature Review Overview

What is a Literature Review? Why Are They Important?

A literature review is important because it presents the "state of the science" or accumulated knowledge on a specific topic. It summarizes, analyzes, and compares the available research, reporting study strengths and weaknesses, results, gaps in the research, conclusions, and authors’ interpretations.

Tips and techniques for conducting a literature review are described more fully in the subsequent boxes:

• Literature review steps
• Strategies for organizing the information for your review
• Literature reviews sections
• In-depth resources to assist in writing a literature review
• Templates to start your review
• Literature review examples

Literature Review Steps

Graphic used with permission: Torres, E. Librarian, Hawai'i Pacific University

1. Choose a topic and define your research question

• Try to choose a topic of interest. You will be working with this subject for several weeks to months.
• Ideas for topics can be found by scanning medical news sources (e.g MedPage Today), journals / magazines, work experiences, interesting patient cases, or family or personal health issues.
• Do a bit of background reading on topic ideas to familiarize yourself with terminology and issues. Note the words and terms that are used.
• Develop a focused research question using PICO(T) or other framework (FINER, SPICE, etc - there are many options) to help guide you.
• Run a few sample database searches to make sure your research question is not too broad or too narrow.
• If possible, discuss your topic with your professor. 

2. Determine the scope of your review

The scope of your review will be determined by your professor during your program. Check your assignment requirements for parameters for the Literature Review.

• How many studies will you need to include?
• How many years should it cover? (usually 5-7 depending on the professor)
• For the nurses, are you required to limit to nursing literature?

3. Develop a search plan

• Determine which databases to search. This will depend on your topic. If you are not sure, check your program specific library website (Physician Asst / Nursing / Health Services Admin) for recommendations.
• Create an initial search string using the main concepts from your research (PICO, etc) question. Include synonyms and related words connected by Boolean operators
• Contact your librarian for assistance, if needed.

4. Conduct searches and find relevant literature

• Keep notes as you search - tracking keywords and search strings used in each database in order to avoid wasting time duplicating a search that has already been tried
• Read abstracts and write down new terms to search as you find them
• Check MeSH or other subject headings listed in relevant articles for additional search terms
• Scan author provided keywords if available
• Check the references of relevant articles looking for other useful articles (ancestry searching)
• Check articles that have cited your relevant article for more useful articles (descendancy searching). Both PubMed and CINAHL offer Cited By links
• Revise the search to broaden or narrow your topic focus as you peruse the available literature
• Conducting a literature search is a repetitive process. Searches can be revised and re-run multiple times during the process.
• Track the citations for your relevant articles in a software citation manager such as RefWorks, Zotero, or Mendeley

5. Review the literature

• Read the full articles. Do not rely solely on the abstracts. Authors frequently cannot include all results within the confines of an abstract. Exclude articles that do not address your research question.
• While reading, note research findings relevant to your project and summarize. Are the findings conflicting? There are matrices available than can help with organization. See the Organizing Information box below.
• Critique / evaluate the quality of the articles, and record your findings in your matrix or summary table. Tools are available to prompt you what to look for. (See Resources for Appraising a Research Study box on the HSA, Nursing , and PA guides )
• You may need to revise your search and re-run it based on your findings.

6. Organize and synthesize

• Compile the findings and analysis from each resource into a single narrative.
• Using an outline can be helpful. Start broad, addressing the overall findings and then narrow, discussing each resource and how it relates to your question and to the other resources.
• Cite as you write to keep sources organized.
• Write in structured paragraphs using topic sentences and transition words to draw connections, comparisons, and contrasts.
• Don't present one study after another, but rather relate one study's findings to another. Speak to how the studies are connected and how they relate to your work.

Organizing Information

Options to assist in organizing sources and information :

1. Synthesis Matrix

• helps provide overview of the literature
• information from individual sources is entered into a grid to enable writers to discern patterns and themes
• article summary, analysis, or results
• thoughts, reflections, or issues
• each reference gets its own row
• mind maps, concept maps, flowcharts
• at top of page record PICO or research question
• record major concepts / themes from literature
• list concepts that branch out from major concepts underneath - keep going downward hierarchically, until most specific ideas are recorded
• enclose concepts in circles and connect the concept with lines - add brief explanation as needed

3. Summary Table

• information is recorded in a grid to help with recall and sorting information when writing
• allows comparing and contrasting individual studies easily
• purpose of study
• methodology (study population, data collection tool)

Efron, S. E., & Ravid, R. (2019). Writing the literature review : A practical guide . Guilford Press.

Literature Review Sections

• Lit reviews can be part of a larger paper / research study or they can be the focus of the paper
• Lit reviews focus on research studies to provide evidence
• New topics may not have much that has been published

* The sections included may depend on the purpose of the literature review (standalone paper or section within a research paper)

Standalone Literature Review (aka Narrative Review):

• presents your topic or PICO question
• includes the why of the literature review and your goals for the review.
• provides background for your the topic and previews the key points
• Narrative Reviews: tmay not have an explanation of methods.
• include where the search was conducted (which databases) what subject terms or keywords were used, and any limits or filters that were applied and why - this will help others re-create the search
• describe how studies were analyzed for inclusion or exclusion
• review the purpose and answer the research question
• thematically - using recurring themes in the literature
• chronologically - present the development of the topic over time
• methodological - compare and contrast findings based on various methodologies used to research the topic (e.g. qualitative vs quantitative, etc.)
• theoretical - organized content based on various theories
• provide an overview of the main points of each source then synthesize the findings into a coherent summary of the whole
• present common themes among the studies
• compare and contrast the various study results
• interpret the results and address the implications of the findings
• do the results support the original hypothesis or conflict with it
• provide your own analysis and interpretation (eg. discuss the significance of findings; evaluate the strengths and weaknesses of the studies, noting any problems)
• discuss common and unusual patterns and offer explanations
•  stay away from opinions, personal biases and unsupported recommendations
• summarize the key findings and relate them back to your PICO/research question
• note gaps in the research and suggest areas for further research
• this section should not contain "new" information that had not been previously discussed in one of the sections above
• provide a list of all the studies and other sources used in proper APA 7

Literature Review as Part of a Research Study Manuscript:

• Compares the study with other research and includes how a study fills a gap in the research.
• Focus on the body of the review which includes the synthesized Findings and Discussion

Literature Reviews vs Systematic Reviews

Systematic Reviews are NOT the same as a Literature Review:

Literature Reviews:

• Literature reviews may or may not follow strict systematic methods to find, select, and analyze articles, but rather they selectively and broadly review the literature on a topic
• Research included in a Literature Review can be "cherry-picked" and therefore, can be very subjective

Systematic Reviews:

• Systemic reviews are designed to provide a comprehensive summary of the evidence for a focused research question
• rigorous and strictly structured, using standardized reporting guidelines (e.g. PRISMA, see link below)
• uses exhaustive, systematic searches of all relevant databases
• best practice dictates search strategies are peer reviewed
• uses predetermined study inclusion and exclusion criteria in order to minimize bias
• aims to capture and synthesize all literature (including unpublished research - grey literature) that meet the predefined criteria on a focused topic resulting in high quality evidence

Literature Review Examples

• Breastfeeding initiation and support: A literature review of what women value and the impact of early discharge (2017). Women and Birth : Journal of the Australian College of Midwives
• Community-based participatory research to promote healthy diet and nutrition and prevent and control obesity among African-Americans: A literature review (2017). Journal of Racial and Ethnic Health Disparities

• Vitamin D deficiency in individuals with a spinal cord injury: A literature review (2017). Spinal Cord

Resources for Writing a Literature Review

These sources have been used in developing this guide.

Resources Used on This Page

Aveyard, H. (2010). Doing a literature review in health and social care : A practical guide . McGraw-Hill Education.

Purdue Online Writing Lab. (n.d.). Writing a literature review . Purdue University. https://owl.purdue.edu/owl/research_and_citation/conducting_research/writing_a_literature_review.html

Torres, E. (2021, October 21). Nursing - graduate studies research guide: Literature review. Hawai'i Pacific University Libraries. Retrieved January 27, 2022, from https://hpu.libguides.com/c.php?g=543891&p=3727230

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JAY SIWEK, M.D., MARGARET L. GOURLAY, M.D., DAVID C. SLAWSON, M.D., AND ALLEN F. SHAUGHNESSY, PHARM.D.

Am Fam Physician. 2002;65(2):251-258

Traditional clinical review articles, also known as updates, differ from systematic reviews and meta-analyses. Updates selectively review the medical literature while discussing a topic broadly. Nonquantitative systematic reviews comprehensively examine the medical literature, seeking to identify and synthesize all relevant information to formulate the best approach to diagnosis or treatment. Meta-analyses (quantitative systematic reviews) seek to answer a focused clinical question, using rigorous statistical analysis of pooled research studies. This article presents guidelines for writing an evidence-based clinical review article for American Family Physician . First, the topic should be of common interest and relevance to family practice. Include a table of the continuing medical education objectives of the review. State how the literature search was done and include several sources of evidence-based reviews, such as the Cochrane Collaboration, BMJ's Clinical Evidence , or the InfoRetriever Web site. Where possible, use evidence based on clinical outcomes relating to morbidity, mortality, or quality of life, and studies of primary care populations. In articles submitted to American Family Physician , rate the level of evidence for key recommendations according to the following scale: level A (randomized controlled trial [RCT], meta-analysis); level B (other evidence); level C (consensus/expert opinion). Finally, provide a table of key summary points.

American Family Physician is particularly interested in receiving clinical review articles that follow an evidence-based format. Clinical review articles, also known as updates, differ from systematic reviews and meta-analyses in important ways. 1 Updates selectively review the medical literature while discussing a topic broadly. An example of such a topic is, “The diagnosis and treatment of myocardial ischemia.” Systematic reviews comprehensively examine the medical literature, seeking to identify and synthesize all relevant information to formulate the best approach to diagnosis or treatment. Examples are many of the systematic reviews of the Cochrane Collaboration or BMJ's Clinical Evidence compendium. Meta-analyses are a special type of systematic review. They use quantitative methods to analyze the literature and seek to answer a focused clinical question, using rigorous statistical analysis of pooled research studies. An example is, “Do beta blockers reduce mortality following myocardial infarction?”

The best clinical review articles base the discussion on existing systematic reviews and meta-analyses, and incorporate all relevant research findings about the management of a given disorder. Such evidence-based updates provide readers with powerful summaries and sound clinical guidance.

In this article, we present guidelines for writing an evidence-based clinical review article, especially one designed for continuing medical education (CME) and incorporating CME objectives into its format. This article may be read as a companion piece to a previous article and accompanying editorial about reading and evaluating clinical review articles. 1 , 2 Some articles may not be appropriate for an evidence-based format because of the nature of the topic, the slant of the article, a lack of sufficient supporting evidence, or other factors. We encourage authors to review the literature and, wherever possible, rate key points of evidence. This process will help emphasize the summary points of the article and strengthen its teaching value.

Topic Selection

Choose a common clinical problem and avoid topics that are rarities or unusual manifestations of disease or that have curiosity value only. Whenever possible, choose common problems for which there is new information about diagnosis or treatment. Emphasize new information that, if valid, should prompt a change in clinical practice, such as the recent evidence that spironolactone therapy improves survival in patients who have severe congestive heart failure. 3 Similarly, new evidence showing that a standard treatment is no longer helpful, but may be harmful, would also be important to report. For example, patching most traumatic corneal abrasions may actually cause more symptoms and delay healing compared with no patching. 4

Searching the Literature

When searching the literature on your topic, please consult several sources of evidence-based reviews ( Table 1 ) . Look for pertinent guidelines on the diagnosis, treatment, or prevention of the disorder being discussed. Incorporate all high-quality recommendations that are relevant to the topic. When reviewing the first draft, look for all key recommendations about diagnosis and, especially, treatment. Try to ensure that all recommendations are based on the highest level of evidence available. If you are not sure about the source or strength of the recommendation, return to the literature, seeking out the basis for the recommendation.

In particular, try to find the answer in an authoritative compendium of evidence-based reviews, or at least try to find a meta-analysis or well-designed randomized controlled trial (RCT) to support it. If none appears to be available, try to cite an authoritative consensus statement or clinical guideline, such as a National Institutes of Health Consensus Development Conference statement or a clinical guideline published by a major medical organization. If no strong evidence exists to support the conventional approach to managing a given clinical situation, point this out in the text, especially for key recommendations. Keep in mind that much of traditional medical practice has not yet undergone rigorous scientific study, and high-quality evidence may not exist to support conventional knowledge or practice.

Patient-Oriented vs. Disease-Oriented Evidence

With regard to types of evidence, Shaughnessy and Slawson 5 – 7 developed the concept of Patient-Oriented Evidence that Matters (POEM), in distinction to Disease-Oriented Evidence (DOE). POEM deals with outcomes of importance to patients, such as changes in morbidity, mortality, or quality of life. DOE deals with surrogate end points, such as changes in laboratory values or other measures of response. Although the results of DOE sometimes parallel the results of POEM, they do not always correspond ( Table 2 ) . 2 When possible, use POEM-type evidence rather than DOE. When DOE is the only guidance available, indicate that key clinical recommendations lack the support of outcomes evidence. Here is an example of how the latter situation might appear in the text: “Although prostate-specific antigen (PSA) testing identifies prostate cancer at an early stage, it has not yet been proved that PSA screening improves patient survival.” (Note: PSA testing is an example of DOE, a surrogate marker for the true outcomes of importance—improved survival, decreased morbidity, and improved quality of life.)

Evaluating the Literature

Evaluate the strength and validity of the literature that supports the discussion (see the following section, Levels of Evidence). Look for meta-analyses, high-quality, randomized clinical trials with important outcomes (POEM), or well-designed, nonrandomized clinical trials, clinical cohort studies, or case-controlled studies with consistent findings. In some cases, high-quality, historical, uncontrolled studies are appropriate (e.g., the evidence supporting the efficacy of Papanicolaou smear screening). Avoid anecdotal reports or repeating the hearsay of conventional wisdom, which may not stand up to the scrutiny of scientific study (e.g., prescribing prolonged bed rest for low back pain).

Look for studies that describe patient populations that are likely to be seen in primary care rather than subspecialty referral populations. Shaughnessy and Slawson's guide for writers of clinical review articles includes a section on information and validity traps to avoid. 2

Levels of Evidence

Readers need to know the strength of the evidence supporting the key clinical recommendations on diagnosis and treatment. Many different rating systems of varying complexity and clinical relevance are described in the medical literature. Recently, the third U.S. Preventive Services Task Force (USPSTF) emphasized the importance of rating not only the study type (RCT, cohort study, case-control study, etc.), but also the study quality as measured by internal validity and the quality of the entire body of evidence on a topic. 8

While it is important to appreciate these evolving concepts, we find that a simplified grading system is more useful in AFP . We have adopted the following convention, using an ABC rating scale. Criteria for high-quality studies are discussed in several sources. 8 , 9 See the AFP Web site ( www.aafp.org/afp/authors ) for additional information about levels of evidence and see the accompanying editorial in this issue discussing the potential pitfalls and limitations of any rating system.

Level A (randomized controlled trial/meta-analysis): High-quality randomized controlled trial (RCT) that considers all important outcomes. High-quality meta-analysis (quantitative systematic review) using comprehensive search strategies.

Level B (other evidence): A well-designed, nonrandomized clinical trial. A nonquantitative systematic review with appropriate search strategies and well-substantiated conclusions. Includes lower quality RCTs, clinical cohort studies, and case-controlled studies with non-biased selection of study participants and consistent findings. Other evidence, such as high-quality, historical, uncontrolled studies, or well-designed epidemiologic studies with compelling findings, is also included.

Level C (consensus/expert opinion): Consensus viewpoint or expert opinion.

Each rating is applied to a single reference in the article, not to the entire body of evidence that exists on a topic. Each label should include the letter rating (A, B, C), followed by the specific type of study for that reference. For example, following a level B rating, include one of these descriptors: (1) nonrandomized clinical trial; (2) nonquantitative systematic review; (3) lower quality RCT; (4) clinical cohort study; (5) case-controlled study; (6) historical uncontrolled study; (7) epidemiologic study.

Here are some examples of the way evidence ratings should appear in the text:

“To improve morbidity and mortality, most patients in congestive heart failure should be treated with an angiotensin-converting enzyme inhibitor. [Evidence level A, RCT]”

“The USPSTF recommends that clinicians routinely screen asymptomatic pregnant women 25 years and younger for chlamydial infection. [Evidence level B, non-randomized clinical trial]”

“The American Diabetes Association recommends screening for diabetes every three years in all patients at high risk of the disease, including all adults 45 years and older. [Evidence level C, expert opinion]”

When scientifically strong evidence does not exist to support a given clinical recommendation, you can point this out in the following way:

“Physical therapy is traditionally prescribed for the treatment of adhesive capsulitis (frozen shoulder), although there are no randomized outcomes studies of this approach.”

Format of the Review

Introduction.

The introduction should define the topic and purpose of the review and describe its relevance to family practice. The traditional way of doing this is to discuss the epidemiology of the condition, stating how many people have it at one point in time (prevalence) or what percentage of the population is expected to develop it over a given period of time (incidence). A more engaging way of doing this is to indicate how often a typical family physician is likely to encounter this problem during a week, month, year, or career. Emphasize the key CME objectives of the review and summarize them in a separate table entitled “CME Objectives.”

The methods section should briefly indicate how the literature search was conducted and what major sources of evidence were used. Ideally, indicate what predetermined criteria were used to include or exclude studies (e.g., studies had to be independently rated as being high quality by an established evaluation process, such as the Cochrane Collaboration). Be comprehensive in trying to identify all major relevant research. Critically evaluate the quality of research reviewed. Avoid selective referencing of only information that supports your conclusions. If there is controversy on a topic, address the full scope of the controversy.

The discussion can then follow the typical format of a clinical review article. It should touch on one or more of the following subtopics: etiology, pathophysiology, clinical presentation (signs and symptoms), diagnostic evaluation (history, physical examination, laboratory evaluation, and diagnostic imaging), differential diagnosis, treatment (goals, medical/surgical therapy, laboratory testing, patient education, and follow-up), prognosis, prevention, and future directions.

The review will be comprehensive and balanced if it acknowledges controversies, unresolved questions, recent developments, other viewpoints, and any apparent conflicts of interest or instances of bias that might affect the strength of the evidence presented. Emphasize an evidence-supported approach or, where little evidence exists, a consensus viewpoint. In the absence of a consensus viewpoint, you may describe generally accepted practices or discuss one or more reasoned approaches, but acknowledge that solid support for these recommendations is lacking.

In some cases, cost-effectiveness analyses may be important in deciding how to implement health care services, especially preventive services. 10 When relevant, mention high-quality cost-effectiveness analyses to help clarify the costs and health benefits associated with alternative interventions to achieve a given health outcome. Highlight key points about diagnosis and treatment in the discussion and include a summary table of the key take-home points. These points are not necessarily the same as the key recommendations, whose level of evidence is rated, although some of them will be.

Use tables, figures, and illustrations to highlight key points, and present a step-wise, algorithmic approach to diagnosis or treatment when possible.

Rate the evidence for key statements, especially treatment recommendations. We expect that most articles will have at most two to four key statements; some will have none. Rate only those statements that have corresponding references and base the rating on the quality and level of evidence presented in the supporting citations. Use primary sources (original research, RCTs, meta-analyses, and systematic reviews) as the basis for determining the level of evidence. In other words, the supporting citation should be a primary research source of the information, not a secondary source (such as a nonsystematic review article or a textbook) that simply cites the original source. Systematic reviews that analyze multiple RCTs are good sources for determining ratings of evidence.

The references should include the most current and important sources of support for key statements (i.e., studies referred to, new information, controversial material, specific quantitative data, and information that would not usually be found in most general reference textbooks). Generally, these references will be key evidence-based recommendations, meta-analyses, or landmark articles. Although some journals publish exhaustive lists of reference citations, AFP prefers to include a succinct list of key references. (We will make more extensive reference lists available on our Web site or provide links to your personal reference list.)

You may use the following checklist to ensure the completeness of your evidence-based review article; use the source list of reviews to identify important sources of evidence-based medicine materials.

Checklist for an Evidence-Based Clinical Review Article

The topic is common in family practice, especially topics in which there is new, important information about diagnosis or treatment.

The introduction defines the topic and the purpose of the review, and describes its relevance to family practice.

A table of CME objectives for the review is included.

The review states how you did your literature search and indicates what sources you checked to ensure a comprehensive assessment of relevant studies (e.g., MEDLINE, the Cochrane Collaboration Database, the Center for Research Support, TRIP Database).

Several sources of evidence-based reviews on the topic are evaluated ( Table 1 ) .

Where possible, POEM (dealing with changes in morbidity, mortality, or quality of life) rather than DOE (dealing with mechanistic explanations or surrogate end points, such as changes in laboratory tests) is used to support key clinical recommendations ( Table 2 ) .

Studies of patients likely to be representative of those in primary care practices, rather than subspecialty referral centers, are emphasized.

Studies that are not only statistically significant but also clinically significant are emphasized; e.g., interventions with meaningful changes in absolute risk reduction and low numbers needed to treat. (See http://www.cebm.net/index.aspx?o=1116 .) 11

The level of evidence for key clinical recommendations is labeled using the following rating scale: level A (RCT/meta-analysis), level B (other evidence), and level C (consensus/expert opinion).

Acknowledge controversies, recent developments, other viewpoints, and any apparent conflicts of interest or instances of bias that might affect the strength of the evidence presented.

Highlight key points about diagnosis and treatment in the discussion and include a summary table of key take-home points.

Use tables, figures, and illustrations to highlight key points and present a step-wise, algorithmic approach to diagnosis or treatment when possible.

Emphasize evidence-based guidelines and primary research studies, rather than other review articles, unless they are systematic reviews.

The essential elements of this checklist are summarized in Table 3 .

Siwek J. Reading and evaluating clinical review articles. Am Fam Physician. 1997;55:2064-2069.

Shaughnessy AF, Slawson DC. Getting the most from review articles: a guide for readers and writers. Am Fam Physician. 1997;55:2155-60.

Pitt B, Zannad F, Remme WJ, Cody R, Castaigne A, Perez A, et al. The effect of spironolactone on morbidity and mortality in patients with severe heart failure. N Engl J Med. 1999;341:709-17.

Flynn CA, D'Amico F, Smith G. Should we patch corneal abrasions? A meta-analysis. J Fam Pract. 1998;47:264-70.

Slawson DC, Shaughnessy AF, Bennett JH. Becoming a medical information master: feeling good about not knowing everything. J Fam Pract. 1994;38:505-13.

Shaughnessy AF, Slawson DC, Bennett JH. Becoming an information master: a guidebook to the medical information jungle. J Fam Pract. 1994;39:489-99.

Slawson DC, Shaughnessy AF. Becoming an information master: using POEMs to change practice with confidence. Patient-oriented evidence that matters. J Fam Pract. 2000;49:63-7.

Harris RP, Helfand M, Woolf SH, Lohr KN, Mulrow CD, Teutsch SM, et al. Methods Work Group, Third U.S. Preventive Services Task Force. Current methods of the U.S. Preventive Services Task Force. A review of the process. Am J Prev Med. 2001;20(3 suppl):21-35.

CATbank topics: levels of evidence and grades of recommendations. Retrieved November 2001, from: http://www.cebm.net/ .

Saha S, Hoerger TJ, Pignone MP, Teutsch SM, Helfand M, Mandelblatt JS. for the Cost Work Group of the Third U.S. Preventive Services Task Force. The art and science of incorporating cost effectiveness into evidence-based recommendations for clinical preventive services. Am J Prev Med. 2001;20(3 suppl):36-43.

Evidence-based medicine glossary. Retrieved November 2001, from: http://www.cebm.net/index.aspx?o=1116 .

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Writing Literature Reviews

What is a literature review.

"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." Source: The Writing Center at UNC-Chapel Hill. (2013). Literature Reviews. Retrieved from https://writingcenter.unc.edu/handouts/literature-reviews/ This link opens in a new window

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The Literature Review: A Foundation for High-Quality Medical Education Research

a  These are subscription resources. Researchers should check with their librarian to determine their access rights.

Despite a surge in published scholarship in medical education 1 and rapid growth in journals that publish educational research, manuscript acceptance rates continue to fall. 2 Failure to conduct a thorough, accurate, and up-to-date literature review identifying an important problem and placing the study in context is consistently identified as one of the top reasons for rejection. 3 , 4 The purpose of this editorial is to provide a road map and practical recommendations for planning a literature review. By understanding the goals of a literature review and following a few basic processes, authors can enhance both the quality of their educational research and the likelihood of publication in the Journal of Graduate Medical Education ( JGME ) and in other journals.

The Literature Review Defined

In medical education, no organization has articulated a formal definition of a literature review for a research paper; thus, a literature review can take a number of forms. Depending on the type of article, target journal, and specific topic, these forms will vary in methodology, rigor, and depth. Several organizations have published guidelines for conducting an intensive literature search intended for formal systematic reviews, both broadly (eg, PRISMA) 5 and within medical education, 6 and there are excellent commentaries to guide authors of systematic reviews. 7 , 8

• A literature review forms the basis for high-quality medical education research and helps maximize relevance, originality, generalizability, and impact.
• A literature review provides context, informs methodology, maximizes innovation, avoids duplicative research, and ensures that professional standards are met.
• Literature reviews take time, are iterative, and should continue throughout the research process.
• Researchers should maximize the use of human resources (librarians, colleagues), search tools (databases/search engines), and existing literature (related articles).
• Keeping organized is critical.

Such work is outside the scope of this article, which focuses on literature reviews to inform reports of original medical education research. We define such a literature review as a synthetic review and summary of what is known and unknown regarding the topic of a scholarly body of work, including the current work's place within the existing knowledge . While this type of literature review may not require the intensive search processes mandated by systematic reviews, it merits a thoughtful and rigorous approach.

Purpose and Importance of the Literature Review

An understanding of the current literature is critical for all phases of a research study. Lingard 9 recently invoked the “journal-as-conversation” metaphor as a way of understanding how one's research fits into the larger medical education conversation. As she described it: “Imagine yourself joining a conversation at a social event. After you hang about eavesdropping to get the drift of what's being said (the conversational equivalent of the literature review), you join the conversation with a contribution that signals your shared interest in the topic, your knowledge of what's already been said, and your intention.” 9

The literature review helps any researcher “join the conversation” by providing context, informing methodology, identifying innovation, minimizing duplicative research, and ensuring that professional standards are met. Understanding the current literature also promotes scholarship, as proposed by Boyer, 10 by contributing to 5 of the 6 standards by which scholarly work should be evaluated. 11 Specifically, the review helps the researcher (1) articulate clear goals, (2) show evidence of adequate preparation, (3) select appropriate methods, (4) communicate relevant results, and (5) engage in reflective critique.

Failure to conduct a high-quality literature review is associated with several problems identified in the medical education literature, including studies that are repetitive, not grounded in theory, methodologically weak, and fail to expand knowledge beyond a single setting. 12 Indeed, medical education scholars complain that many studies repeat work already published and contribute little new knowledge—a likely cause of which is failure to conduct a proper literature review. 3 , 4

Likewise, studies that lack theoretical grounding or a conceptual framework make study design and interpretation difficult. 13 When theory is used in medical education studies, it is often invoked at a superficial level. As Norman 14 noted, when theory is used appropriately, it helps articulate variables that might be linked together and why, and it allows the researcher to make hypotheses and define a study's context and scope. Ultimately, a proper literature review is a first critical step toward identifying relevant conceptual frameworks.

Another problem is that many medical education studies are methodologically weak. 12 Good research requires trained investigators who can articulate relevant research questions, operationally define variables of interest, and choose the best method for specific research questions. Conducting a proper literature review helps both novice and experienced researchers select rigorous research methodologies.

Finally, many studies in medical education are “one-offs,” that is, single studies undertaken because the opportunity presented itself locally. Such studies frequently are not oriented toward progressive knowledge building and generalization to other settings. A firm grasp of the literature can encourage a programmatic approach to research.

Approaching the Literature Review

Considering these issues, journals have a responsibility to demand from authors a thoughtful synthesis of their study's position within the field, and it is the authors' responsibility to provide such a synthesis, based on a literature review. The aforementioned purposes of the literature review mandate that the review occurs throughout all phases of a study, from conception and design, to implementation and analysis, to manuscript preparation and submission.

Planning the literature review requires understanding of journal requirements, which vary greatly by journal ( table 1 ). Authors are advised to take note of common problems with reporting results of the literature review. Table 2 lists the most common problems that we have encountered as authors, reviewers, and editors.

Sample of Journals' Author Instructions for Literature Reviews Conducted as Part of Original Research Article a

Common Problem Areas for Reporting Literature Reviews in the Context of Scholarly Articles

Locating and Organizing the Literature

Three resources may facilitate identifying relevant literature: human resources, search tools, and related literature. As the process requires time, it is important to begin searching for literature early in the process (ie, the study design phase). Identifying and understanding relevant studies will increase the likelihood of designing a relevant, adaptable, generalizable, and novel study that is based on educational or learning theory and can maximize impact.

Human Resources

A medical librarian can help translate research interests into an effective search strategy, familiarize researchers with available information resources, provide information on organizing information, and introduce strategies for keeping current with emerging research. Often, librarians are also aware of research across their institutions and may be able to connect researchers with similar interests. Reaching out to colleagues for suggestions may help researchers quickly locate resources that would not otherwise be on their radar.

During this process, researchers will likely identify other researchers writing on aspects of their topic. Researchers should consider searching for the publications of these relevant researchers (see table 3 for search strategies). Additionally, institutional websites may include curriculum vitae of such relevant faculty with access to their entire publication record, including difficult to locate publications, such as book chapters, dissertations, and technical reports.

Strategies for Finding Related Researcher Publications in Databases and Search Engines

Search Tools and Related Literature

Researchers will locate the majority of needed information using databases and search engines. Excellent resources are available to guide researchers in the mechanics of literature searches. 15 , 16

Because medical education research draws on a variety of disciplines, researchers should include search tools with coverage beyond medicine (eg, psychology, nursing, education, and anthropology) and that cover several publication types, such as reports, standards, conference abstracts, and book chapters (see the box for several information resources). Many search tools include options for viewing citations of selected articles. Examining cited references provides additional articles for review and a sense of the influence of the selected article on its field.

Box Information Resources

• Web of Science a
• Education Resource Information Center (ERIC)
• Cumulative Index of Nursing & Allied Health (CINAHL) a
• Google Scholar

Once relevant articles are located, it is useful to mine those articles for additional citations. One strategy is to examine references of key articles, especially review articles, for relevant citations.

Getting Organized

As the aforementioned resources will likely provide a tremendous amount of information, organization is crucial. Researchers should determine which details are most important to their study (eg, participants, setting, methods, and outcomes) and generate a strategy for keeping those details organized and accessible. Increasingly, researchers utilize digital tools, such as Evernote, to capture such information, which enables accessibility across digital workspaces and search capabilities. Use of citation managers can also be helpful as they store citations and, in some cases, can generate bibliographies ( table 4 ).

Citation Managers

Knowing When to Say When

Researchers often ask how to know when they have located enough citations. Unfortunately, there is no magic or ideal number of citations to collect. One strategy for checking coverage of the literature is to inspect references of relevant articles. As researchers review references they will start noticing a repetition of the same articles with few new articles appearing. This can indicate that the researcher has covered the literature base on a particular topic.

Putting It All Together

In preparing to write a research paper, it is important to consider which citations to include and how they will inform the introduction and discussion sections. The “Instructions to Authors” for the targeted journal will often provide guidance on structuring the literature review (or introduction) and the number of total citations permitted for each article category. Reviewing articles of similar type published in the targeted journal can also provide guidance regarding structure and average lengths of the introduction and discussion sections.

When selecting references for the introduction consider those that illustrate core background theoretical and methodological concepts, as well as recent relevant studies. The introduction should be brief and present references not as a laundry list or narrative of available literature, but rather as a synthesized summary to provide context for the current study and to identify the gap in the literature that the study intends to fill. For the discussion, citations should be thoughtfully selected to compare and contrast the present study's findings with the current literature and to indicate how the present study moves the field forward.

To facilitate writing a literature review, journals are increasingly providing helpful features to guide authors. For example, the resources available through JGME include several articles on writing. 17 The journal Perspectives on Medical Education recently launched “The Writer's Craft,” which is intended to help medical educators improve their writing. Additionally, many institutions have writing centers that provide web-based materials on writing a literature review, and some even have writing coaches.

The literature review is a vital part of medical education research and should occur throughout the research process to help researchers design a strong study and effectively communicate study results and importance. To achieve these goals, researchers are advised to plan and execute the literature review carefully. The guidance in this editorial provides considerations and recommendations that may improve the quality of literature reviews.

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Literature review

Literature reviews are a way of identifying what is already known about a research area and what the gaps are. To do a literature review, you will need to identify relevant literature, often through searching academic databases, and then review existing literature. Most often, you will do the literature review at the beginning of your research project, but it is iterative, so you may choose to change the literature review as you move through your project.

Searching the literature

The University of Melbourne Library has some resources about searching the literature. Leonie spoke about how she met with a librarian about searching the literature. You may also want to meet face-to-face with a librarian or attend a class at the library to learn more about literature searching. When you search the literature, you may find journal articles, reports, books and other materials.

Filing, categorising and managing literature

In order to manage the literature you have identified through searches, you may choose to use a reference manager. The University of Melbourne has access to RefWorks and Endnote. Further information about accessing this software is available through the University of Melbourne Library .

Writing a literature review

The purpose of the literature review is to identify what is already known about a particular research area and critically analyse prior studies. It will also help you to identify any gaps in the research and situate your research in what is already known about a particular topic.

• Aveyard, H. (2010). Doing a literature review in health and social care: A practical guide . London, UK: McGraw-Hill Education. Retrieved from Proquest https://ebookcentral.proquest.com/lib/unimelb/detail.action?docID=771406
• Reeves, S., Koppel, I., Barr, H., Freeth, D., Hammick, M. (2002). Twelve tips for undertaking a systematic review. Medical Teacher . 24(4), 358-363 .
• Grant, M.J. and Booth, A. (2009). A typology of reviews: an analysis of 14 review types and associated methodologies. Health Information & Libraries Journal .
• Jesson, J., & Lacey, F. (2006). How to do (or not to do) a critical literature review. Pharmacy Education , 6(2), 139-148 .
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