How Long Should the Introduction of a Research Paper Be? Data from 61,518 Examples

I analyzed a random sample of 61,518 full-text research papers, uploaded to PubMed Central between the years 2016 and 2021, in order to answer the questions:

What is the typical length of an introduction section? and which factors influence it?

I used the BioC API to download the data (see the References section below).

Here’s a summary of the key findings

1. The median introduction was 553 words long (equivalent to 21 sentences, or 4 paragraphs), and 90% of the introductions were between 245 and 1,245 words.

2. The introduction is the shortest section of the research paper (14.6% of the total word count), approximately half the length of other sections (Methods, Results, and Discussion).

3. The length of the introduction does not differ between review articles and original research articles .

4. The quality of the journal does not influence the length of the introduction section .

Overall length of the introduction section

Here’s a table that describes the length of an introduction in terms of words, sentences, and paragraphs:

From these data, we can conclude that most research papers have a 3 to 5 paragraph introductions (consisting of 15 to 28 sentences).

If you are interested, here’s the link to the PubMed article that had the longest introduction of 9,776 words, 426 sentences, and 196 paragraphs!

The introduction constitutes 14.6% of the total word count of a research paper, nearly half the length of other sections (Methods, Results, and Discussion) [source: How Long Should a Research Paper Be? ].

Length of the introduction for different article types

The following table shows the median word count of the introduction section for different study designs:

The data show no clear pattern since the introductions of review articles and original research articles have almost similar word counts. So we can conclude that there is no particular article type that requires a longer introduction section.

Length of the introduction in different journals

In order to study the influence of the journal quality on the length of the introduction, I ran a Poisson regression that models the introduction word count given the journal impact factor. Here’s the model output:

The model shows that a higher journal impact factor is associated with a longer introduction. Although statistically significant, this result is practically negligible since an increase of 1 unit in the journal impact factor is associated with an increase of only 0.8% in the introduction word count.

  • Comeau DC, Wei CH, Islamaj Doğan R, and Lu Z. PMC text mining subset in BioC: about 3 million full text articles and growing,  Bioinformatics , btz070, 2019.

Further reading

  • How Long Should the Methods Section Be? Data from 61,514 Examples
  • How Many References to Cite? Based on 96,685 Research Papers
  • How Old Should References Be? Based on 3,823,919 Examples
  • Length of a Conclusion Section: Analysis of 47,810 Examples
  • Statistical Software Popularity in 40,582 Research Papers
  • Programming Languages Popularity in 12,086 Research Papers
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Home » Research Paper Introduction – Writing Guide and Examples

Research Paper Introduction – Writing Guide and Examples

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Research Paper Introduction

Research Paper Introduction

Research paper introduction is the first section of a research paper that provides an overview of the study, its purpose, and the research question (s) or hypothesis (es) being investigated. It typically includes background information about the topic, a review of previous research in the field, and a statement of the research objectives. The introduction is intended to provide the reader with a clear understanding of the research problem, why it is important, and how the study will contribute to existing knowledge in the field. It also sets the tone for the rest of the paper and helps to establish the author’s credibility and expertise on the subject.

How to Write Research Paper Introduction

Writing an introduction for a research paper can be challenging because it sets the tone for the entire paper. Here are some steps to follow to help you write an effective research paper introduction:

  • Start with a hook : Begin your introduction with an attention-grabbing statement, a question, or a surprising fact that will make the reader interested in reading further.
  • Provide background information: After the hook, provide background information on the topic. This information should give the reader a general idea of what the topic is about and why it is important.
  • State the research problem: Clearly state the research problem or question that the paper addresses. This should be done in a concise and straightforward manner.
  • State the research objectives: After stating the research problem, clearly state the research objectives. This will give the reader an idea of what the paper aims to achieve.
  • Provide a brief overview of the paper: At the end of the introduction, provide a brief overview of the paper. This should include a summary of the main points that will be discussed in the paper.
  • Revise and refine: Finally, revise and refine your introduction to ensure that it is clear, concise, and engaging.

Structure of Research Paper Introduction

The following is a typical structure for a research paper introduction:

  • Background Information: This section provides an overview of the topic of the research paper, including relevant background information and any previous research that has been done on the topic. It helps to give the reader a sense of the context for the study.
  • Problem Statement: This section identifies the specific problem or issue that the research paper is addressing. It should be clear and concise, and it should articulate the gap in knowledge that the study aims to fill.
  • Research Question/Hypothesis : This section states the research question or hypothesis that the study aims to answer. It should be specific and focused, and it should clearly connect to the problem statement.
  • Significance of the Study: This section explains why the research is important and what the potential implications of the study are. It should highlight the contribution that the research makes to the field.
  • Methodology: This section describes the research methods that were used to conduct the study. It should be detailed enough to allow the reader to understand how the study was conducted and to evaluate the validity of the results.
  • Organization of the Paper : This section provides a brief overview of the structure of the research paper. It should give the reader a sense of what to expect in each section of the paper.

Research Paper Introduction Examples

Research Paper Introduction Examples could be:

Example 1: In recent years, the use of artificial intelligence (AI) has become increasingly prevalent in various industries, including healthcare. AI algorithms are being developed to assist with medical diagnoses, treatment recommendations, and patient monitoring. However, as the use of AI in healthcare grows, ethical concerns regarding privacy, bias, and accountability have emerged. This paper aims to explore the ethical implications of AI in healthcare and propose recommendations for addressing these concerns.

Example 2: Climate change is one of the most pressing issues facing our planet today. The increasing concentration of greenhouse gases in the atmosphere has resulted in rising temperatures, changing weather patterns, and other environmental impacts. In this paper, we will review the scientific evidence on climate change, discuss the potential consequences of inaction, and propose solutions for mitigating its effects.

Example 3: The rise of social media has transformed the way we communicate and interact with each other. While social media platforms offer many benefits, including increased connectivity and access to information, they also present numerous challenges. In this paper, we will examine the impact of social media on mental health, privacy, and democracy, and propose solutions for addressing these issues.

Example 4: The use of renewable energy sources has become increasingly important in the face of climate change and environmental degradation. While renewable energy technologies offer many benefits, including reduced greenhouse gas emissions and energy independence, they also present numerous challenges. In this paper, we will assess the current state of renewable energy technology, discuss the economic and political barriers to its adoption, and propose solutions for promoting the widespread use of renewable energy.

Purpose of Research Paper Introduction

The introduction section of a research paper serves several important purposes, including:

  • Providing context: The introduction should give readers a general understanding of the topic, including its background, significance, and relevance to the field.
  • Presenting the research question or problem: The introduction should clearly state the research question or problem that the paper aims to address. This helps readers understand the purpose of the study and what the author hopes to accomplish.
  • Reviewing the literature: The introduction should summarize the current state of knowledge on the topic, highlighting the gaps and limitations in existing research. This shows readers why the study is important and necessary.
  • Outlining the scope and objectives of the study: The introduction should describe the scope and objectives of the study, including what aspects of the topic will be covered, what data will be collected, and what methods will be used.
  • Previewing the main findings and conclusions : The introduction should provide a brief overview of the main findings and conclusions that the study will present. This helps readers anticipate what they can expect to learn from the paper.

When to Write Research Paper Introduction

The introduction of a research paper is typically written after the research has been conducted and the data has been analyzed. This is because the introduction should provide an overview of the research problem, the purpose of the study, and the research questions or hypotheses that will be investigated.

Once you have a clear understanding of the research problem and the questions that you want to explore, you can begin to write the introduction. It’s important to keep in mind that the introduction should be written in a way that engages the reader and provides a clear rationale for the study. It should also provide context for the research by reviewing relevant literature and explaining how the study fits into the larger field of research.

Advantages of Research Paper Introduction

The introduction of a research paper has several advantages, including:

  • Establishing the purpose of the research: The introduction provides an overview of the research problem, question, or hypothesis, and the objectives of the study. This helps to clarify the purpose of the research and provide a roadmap for the reader to follow.
  • Providing background information: The introduction also provides background information on the topic, including a review of relevant literature and research. This helps the reader understand the context of the study and how it fits into the broader field of research.
  • Demonstrating the significance of the research: The introduction also explains why the research is important and relevant. This helps the reader understand the value of the study and why it is worth reading.
  • Setting expectations: The introduction sets the tone for the rest of the paper and prepares the reader for what is to come. This helps the reader understand what to expect and how to approach the paper.
  • Grabbing the reader’s attention: A well-written introduction can grab the reader’s attention and make them interested in reading further. This is important because it can help to keep the reader engaged and motivated to read the rest of the paper.
  • Creating a strong first impression: The introduction is the first part of the research paper that the reader will see, and it can create a strong first impression. A well-written introduction can make the reader more likely to take the research seriously and view it as credible.
  • Establishing the author’s credibility: The introduction can also establish the author’s credibility as a researcher. By providing a clear and thorough overview of the research problem and relevant literature, the author can demonstrate their expertise and knowledge in the field.
  • Providing a structure for the paper: The introduction can also provide a structure for the rest of the paper. By outlining the main sections and sub-sections of the paper, the introduction can help the reader navigate the paper and find the information they are looking for.

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How to Write an Introduction for a Research Paper

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How to write an introduction for a research paper? Eventually (and with practice) all writers will develop their own strategy for writing the perfect introduction for a research paper. Once you are comfortable with writing, you will probably find your own, but coming up with a good strategy can be tough for beginning writers.

The Purpose of an Introduction

Your opening paragraphs, phrases for introducing thesis statements, research paper introduction examples, using the introduction to map out your research paper.

How to Write an Introduction for a Research Paper

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  • First write your thesis.Your thesis should state the main idea in specific terms.
  • After you have a working thesis, tackle the body of your paper before you write the rest of the introduction. Each paragraph in the body should explore one specific topic that proves, or summarizes your thesis. Writing is a thinking process. Once you have worked your way through that process by writing the body of the paper, you will have an intimate understanding of how you are supporting your thesis. After you have written the body paragraphs, go back and rewrite your thesis to make it more specific and to connect it to the topics you addressed in the body paragraph.
  • Revise your introduction several times, saving each revision. Be sure your introduction previews the topics you are presenting in your paper. One way of doing this is to use keywords from the topic sentences in each paragraph to introduce, or preview, the topics in your introduction.This “preview” will give your reader a context for understanding how you will make your case.
  • Experiment by taking different approaches to your thesis with every revision you make. Play with the language in the introduction. Strike a new tone. Go back and compare versions. Then pick the one that works most effectively with the body of your research paper.
  • Do not try to pack everything you want to say into your introduction. Just as your introduction should not be too short, it should also not be too long. Your introduction should be about the same length as any other paragraph in your research paper. Let the content—what you have to say—dictate the length.

The first page of your research paper should draw the reader into the text. It is the paper’s most important page and, alas, often the worst written. There are two culprits here and effective ways to cope with both of them.

First, the writer is usually straining too hard to say something terribly BIG and IMPORTANT about the thesis topic. The goal is worthy, but the aim is unrealistically high. The result is often a muddle of vague platitudes rather than a crisp, compelling introduction to the thesis. Want a familiar example? Listen to most graduation speakers. Their goal couldn’t be loftier: to say what education means and to tell an entire football stadium how to live the rest of their lives. The results are usually an avalanche of clichés and sodden prose.

The second culprit is bad timing. The opening and concluding paragraphs are usually written late in the game, after the rest of the thesis is finished and polished. There’s nothing wrong with writing these sections last. It’s usually the right approach since you need to know exactly what you are saying in the substantive middle sections of the thesis before you can introduce them effectively or draw together your findings. But having waited to write the opening and closing sections, you need to review and edit them several times to catch up. Otherwise, you’ll putting the most jagged prose in the most tender spots. Edit and polish your opening paragraphs with extra care. They should draw readers into the paper.

After you’ve done some extra polishing, I suggest a simple test for the introductory section. As an experiment, chop off the first few paragraphs. Let the paper begin on, say, paragraph 2 or even page 2. If you don’t lose much, or actually gain in clarity and pace, then you’ve got a problem.

There are two solutions. One is to start at this new spot, further into the text. After all, that’s where you finally gain traction on your subject. That works best in some cases, and we occasionally suggest it. The alternative, of course, is to write a new opening that doesn’t flop around, saying nothing.

What makes a good opening? Actually, they come in several flavors. One is an intriguing story about your topic. Another is a brief, compelling quote. When you run across them during your reading, set them aside for later use. Don’t be deterred from using them because they “don’t seem academic enough.” They’re fine as long as the rest of the paper doesn’t sound like you did your research in People magazine. The third, and most common, way to begin is by stating your main questions, followed by a brief comment about why they matter.

Whichever opening you choose, it should engage your readers and coax them to continue. Having done that, you should give them a general overview of the project—the main issues you will cover, the material you will use, and your thesis statement (that is, your basic approach to the topic). Finally, at the end of the introductory section, give your readers a brief road map, showing how the paper will unfold. How you do that depends on your topic but here are some general suggestions for phrase choice that may help:

  • This analysis will provide …
  • This paper analyzes the relationship between …
  • This paper presents an analysis of …
  • This paper will argue that …
  • This topic supports the argument that…
  • Research supports the opinion that …
  • This paper supports the opinion that …
  • An interpretation of the facts indicates …
  • The results of this experiment show …
  • The results of this research show …

Comparisons/Contrasts

  • A comparison will show that …
  • By contrasting the results,we see that …
  • This paper examines the advantages and disadvantages of …

Definitions/Classifications

  • This paper will provide a guide for categorizing the following:…
  • This paper provides a definition of …
  • This paper explores the meaning of …
  • This paper will discuss the implications of …
  • A discussion of this topic reveals …
  • The following discussion will focus on …

Description

  • This report describes…
  • This report will illustrate…
  • This paper provides an illustration of …

Process/Experimentation

  • This paper will identify the reasons behind…
  • The results of the experiment show …
  • The process revealed that …
  • This paper theorizes…
  • This paper presents the theory that …
  • In theory, this indicates that …

Quotes, anecdotes, questions, examples, and broad statements—all of them can used successfully to write an introduction for a research paper. It’s instructive to see them in action, in the hands of skilled academic writers.

Let’s begin with David M. Kennedy’s superb history, Freedom from Fear: The American People in Depression and War, 1929–1945 . Kennedy begins each chapter with a quote, followed by his text. The quote above chapter 1 shows President Hoover speaking in 1928 about America’s golden future. The text below it begins with the stock market collapse of 1929. It is a riveting account of just how wrong Hoover was. The text about the Depression is stronger because it contrasts so starkly with the optimistic quotation.

“We in America today are nearer the final triumph over poverty than ever before in the history of any land.”—Herbert Hoover, August 11, 1928 Like an earthquake, the stock market crash of October 1929 cracked startlingly across the United States, the herald of a crisis that was to shake the American way of life to its foundations. The events of the ensuing decade opened a fissure across the landscape of American history no less gaping than that opened by the volley on Lexington Common in April 1775 or by the bombardment of Sumter on another April four score and six years later. The ratcheting ticker machines in the autumn of 1929 did not merely record avalanching stock prices. In time they came also to symbolize the end of an era. (David M. Kennedy, Freedom from Fear: The American People in Depression and War, 1929–1945 . New York: Oxford University Press, 1999, p. 10)

Kennedy has exciting, wrenching material to work with. John Mueller faces the exact opposite problem. In Retreat from Doomsday: The Obsolescence of Major War , he is trying to explain why Great Powers have suddenly stopped fighting each other. For centuries they made war on each other with devastating regularity, killing millions in the process. But now, Mueller thinks, they have not just paused; they have stopped permanently. He is literally trying to explain why “nothing is happening now.” That may be an exciting topic intellectually, it may have great practical significance, but “nothing happened” is not a very promising subject for an exciting opening paragraph. Mueller manages to make it exciting and, at the same time, shows why it matters so much. Here’s his opening, aptly entitled “History’s Greatest Nonevent”:

On May 15, 1984, the major countries of the developed world had managed to remain at peace with each other for the longest continuous stretch of time since the days of the Roman Empire. If a significant battle in a war had been fought on that day, the press would have bristled with it. As usual, however, a landmark crossing in the history of peace caused no stir: the most prominent story in the New York Times that day concerned the saga of a manicurist, a machinist, and a cleaning woman who had just won a big Lotto contest. This book seeks to develop an explanation for what is probably the greatest nonevent in human history. (John Mueller, Retreat from Doomsday: The Obsolescence of Major War . New York: Basic Books, 1989, p. 3)

In the space of a few sentences, Mueller sets up his puzzle and reveals its profound human significance. At the same time, he shows just how easy it is to miss this milestone in the buzz of daily events. Notice how concretely he does that. He doesn’t just say that the New York Times ignored this record setting peace. He offers telling details about what they covered instead: “a manicurist, a machinist, and a cleaning woman who had just won a big Lotto contest.” Likewise, David Kennedy immediately entangles us in concrete events: the stunning stock market crash of 1929. These are powerful openings that capture readers’ interests, establish puzzles, and launch narratives.

Sociologist James Coleman begins in a completely different way, by posing the basic questions he will study. His ambitious book, Foundations of Social Theory , develops a comprehensive theory of social life, so it is entirely appropriate for him to begin with some major questions. But he could just as easily have begun with a compelling story or anecdote. He includes many of them elsewhere in his book. His choice for the opening, though, is to state his major themes plainly and frame them as a paradox. Sociologists, he says, are interested in aggregate behavior—how people act in groups, organizations, or large numbers—yet they mostly examine individuals:

A central problem in social science is that of accounting for the function of some kind of social system. Yet in most social research, observations are not made on the system as a whole, but on some part of it. In fact, the natural unit of observation is the individual person…  This has led to a widening gap between theory and research… (James S. Coleman, Foundations of Social Theory . Cambridge, MA: Harvard University Press, 1990, pp. 1–2)

After expanding on this point, Coleman explains that he will not try to remedy the problem by looking solely at groups or aggregate-level data. That’s a false solution, he says, because aggregates don’t act; individuals do. So the real problem is to show the links between individual actions and aggregate outcomes, between the micro and the macro.

The major problem for explanations of system behavior based on actions and orientations at a level below that of the system [in this case, on individual-level actions] is that of moving from the lower level to the system level. This has been called the micro-to-macro problem, and it is pervasive throughout the social sciences. (Coleman, Foundations of Social Theory , p. 6)

Explaining how to deal with this “micro-to-macro problem” is the central issue of Coleman’s book, and he announces it at the beginning.

Coleman’s theory-driven opening stands at the opposite end of the spectrum from engaging stories or anecdotes, which are designed to lure the reader into the narrative and ease the path to a more analytic treatment later in the text. Take, for example, the opening sentences of Robert L. Herbert’s sweeping study Impressionism: Art, Leisure, and Parisian Society : “When Henry Tuckerman came to Paris in 1867, one of the thousands of Americans attracted there by the huge international exposition, he was bowled over by the extraordinary changes since his previous visit twenty years before.” (Robert L. Herbert, Impressionism: Art, Leisure, and Parisian Society . New Haven, CT: Yale University Press, 1988, p. 1.) Herbert fills in the evocative details to set the stage for his analysis of the emerging Impressionist art movement and its connection to Parisian society and leisure in this period.

David Bromwich writes about Wordsworth, a poet so familiar to students of English literature that it is hard to see him afresh, before his great achievements, when he was just a young outsider starting to write. To draw us into Wordsworth’s early work, Bromwich wants us to set aside our entrenched images of the famous mature poet and see him as he was in the 1790s, as a beginning writer on the margins of society. He accomplishes this ambitious task in the opening sentences of Disowned by Memory: Wordsworth’s Poetry of the 1790s :

Wordsworth turned to poetry after the revolution to remind himself that he was still a human being. It was a curious solution, to a difficulty many would not have felt. The whole interest of his predicament is that he did feel it. Yet Wordsworth is now so established an eminence—his name so firmly fixed with readers as a moralist of self-trust emanating from complete self-security—that it may seem perverse to imagine him as a criminal seeking expiation. Still, that is a picture we get from The Borderers and, at a longer distance, from “Tintern Abbey.” (David Bromwich, Disowned by Memory: Wordsworth’s Poetry of the 1790s . Chicago: University of Chicago Press, 1998, p. 1)

That’s a wonderful opening! Look at how much Bromwich accomplishes in just a few words. He not only prepares the way for analyzing Wordsworth’s early poetry; he juxtaposes the anguished young man who wrote it to the self-confident, distinguished figure he became—the eminent man we can’t help remembering as we read his early poetry.

Let us highlight a couple of other points in this passage because they illustrate some intelligent writing choices. First, look at the odd comma in this sentence: “It was a curious solution, to a difficulty many would not have felt.” Any standard grammar book would say that comma is wrong and should be omitted. Why did Bromwich insert it? Because he’s a fine writer, thinking of his sentence rhythm and the point he wants to make. The comma does exactly what it should. It makes us pause, breaking the sentence into two parts, each with an interesting point. One is that Wordsworth felt a difficulty others would not have; the other is that he solved it in a distinctive way. It would be easy for readers to glide over this double message, so Bromwich has inserted a speed bump to slow us down. Most of the time, you should follow grammatical rules, like those about commas, but you should bend them when it serves a good purpose. That’s what the writer does here.

The second small point is the phrase “after the revolution” in the first sentence: “Wordsworth turned to poetry after the revolution to remind himself that he was still a human being.” Why doesn’t Bromwich say “after the French Revolution”? Because he has judged his book’s audience. He is writing for specialists who already know which revolution is reverberating through English life in the 1790s. It is the French Revolution, not the earlier loss of the American colonies. If Bromwich were writing for a much broader audience—say, the New York Times Book Review—he would probably insert the extra word to avoid confusion.

The message “Know your audience” applies to all writers. Don’t talk down to them by assuming they can’t get dressed in the morning. Don’t strut around showing off your book learnin’ by tossing in arcane facts and esoteric language for its own sake. Neither will win over readers.

Bromwich, Herbert, and Coleman open their works in different ways, but their choices work well for their different texts. Your task is to decide what kind of opening will work best for yours. Don’t let that happen by default, by grabbing the first idea you happen upon. Consider a couple of different ways of opening your thesis and then choose the one you prefer. Give yourself some options, think them over, then make an informed choice.

Whether you begin with a story, puzzle, or broad statement, the next part of the introduction should pose your main questions and establish your argument. This is your thesis statement—your viewpoint along with the supporting reasons and evidence. It should be articulated plainly so readers understand full well what your paper is about and what it will argue.

After that, give your readers a road map of what’s to come. That’s normally done at the end of the introductory section (or, in a book, at the end of the introductory chapter). Here’s John J. Mearsheimer presenting such a road map in The Tragedy of Great Power Politics . He not only tells us the order of upcoming chapters, he explains why he’s chosen that order and which chapters are most important:

The Plan of the Book The rest of the chapters in this book are concerned mainly with answering the six big questions about power which I identified earlier. Chapter 2, which is probably the most important chapter in the book, lays out my theory of why states compete for power and why they pursue hegemony. In Chapters 3 and 4, I define power and explain how to measure it. I do this in order to lay the groundwork for testing my theory… (John J. Mearsheimer, The Tragedy of Great Power Politics . New York: W. W. Norton, 2001, p. 27)

As this excerpt makes clear, Mearsheimer has already laid out his “six big questions” in the introduction. Now he’s showing us the path ahead, the path to answering those questions.

At the end of the introduction, give your readers a road map of what’s to come. Tell them what the upcoming sections will be and why they are arranged in this particular order.

After having written your introduction it’s time to move to the biggest part: body of a research paper.

Back to How To Write A Research Paper .

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The introduction leads the reader from a general subject area to a particular topic of inquiry. It establishes the scope, context, and significance of the research being conducted by summarizing current understanding and background information about the topic, stating the purpose of the work in the form of the research problem supported by a hypothesis or a set of questions, explaining briefly the methodological approach used to examine the research problem, highlighting the potential outcomes your study can reveal, and outlining the remaining structure and organization of the paper.

Key Elements of the Research Proposal. Prepared under the direction of the Superintendent and by the 2010 Curriculum Design and Writing Team. Baltimore County Public Schools.

Importance of a Good Introduction

Think of the introduction as a mental road map that must answer for the reader these four questions:

  • What was I studying?
  • Why was this topic important to investigate?
  • What did we know about this topic before I did this study?
  • How will this study advance new knowledge or new ways of understanding?

According to Reyes, there are three overarching goals of a good introduction: 1) ensure that you summarize prior studies about the topic in a manner that lays a foundation for understanding the research problem; 2) explain how your study specifically addresses gaps in the literature, insufficient consideration of the topic, or other deficiency in the literature; and, 3) note the broader theoretical, empirical, and/or policy contributions and implications of your research.

A well-written introduction is important because, quite simply, you never get a second chance to make a good first impression. The opening paragraphs of your paper will provide your readers with their initial impressions about the logic of your argument, your writing style, the overall quality of your research, and, ultimately, the validity of your findings and conclusions. A vague, disorganized, or error-filled introduction will create a negative impression, whereas, a concise, engaging, and well-written introduction will lead your readers to think highly of your analytical skills, your writing style, and your research approach. All introductions should conclude with a brief paragraph that describes the organization of the rest of the paper.

Hirano, Eliana. “Research Article Introductions in English for Specific Purposes: A Comparison between Brazilian, Portuguese, and English.” English for Specific Purposes 28 (October 2009): 240-250; Samraj, B. “Introductions in Research Articles: Variations Across Disciplines.” English for Specific Purposes 21 (2002): 1–17; Introductions. The Writing Center. University of North Carolina; “Writing Introductions.” In Good Essay Writing: A Social Sciences Guide. Peter Redman. 4th edition. (London: Sage, 2011), pp. 63-70; Reyes, Victoria. Demystifying the Journal Article. Inside Higher Education.

Structure and Writing Style

I.  Structure and Approach

The introduction is the broad beginning of the paper that answers three important questions for the reader:

  • What is this?
  • Why should I read it?
  • What do you want me to think about / consider doing / react to?

Think of the structure of the introduction as an inverted triangle of information that lays a foundation for understanding the research problem. Organize the information so as to present the more general aspects of the topic early in the introduction, then narrow your analysis to more specific topical information that provides context, finally arriving at your research problem and the rationale for studying it [often written as a series of key questions to be addressed or framed as a hypothesis or set of assumptions to be tested] and, whenever possible, a description of the potential outcomes your study can reveal.

These are general phases associated with writing an introduction: 1.  Establish an area to research by:

  • Highlighting the importance of the topic, and/or
  • Making general statements about the topic, and/or
  • Presenting an overview on current research on the subject.

2.  Identify a research niche by:

  • Opposing an existing assumption, and/or
  • Revealing a gap in existing research, and/or
  • Formulating a research question or problem, and/or
  • Continuing a disciplinary tradition.

3.  Place your research within the research niche by:

  • Stating the intent of your study,
  • Outlining the key characteristics of your study,
  • Describing important results, and
  • Giving a brief overview of the structure of the paper.

NOTE:   It is often useful to review the introduction late in the writing process. This is appropriate because outcomes are unknown until you've completed the study. After you complete writing the body of the paper, go back and review introductory descriptions of the structure of the paper, the method of data gathering, the reporting and analysis of results, and the conclusion. Reviewing and, if necessary, rewriting the introduction ensures that it correctly matches the overall structure of your final paper.

II.  Delimitations of the Study

Delimitations refer to those characteristics that limit the scope and define the conceptual boundaries of your research . This is determined by the conscious exclusionary and inclusionary decisions you make about how to investigate the research problem. In other words, not only should you tell the reader what it is you are studying and why, but you must also acknowledge why you rejected alternative approaches that could have been used to examine the topic.

Obviously, the first limiting step was the choice of research problem itself. However, implicit are other, related problems that could have been chosen but were rejected. These should be noted in the conclusion of your introduction. For example, a delimitating statement could read, "Although many factors can be understood to impact the likelihood young people will vote, this study will focus on socioeconomic factors related to the need to work full-time while in school." The point is not to document every possible delimiting factor, but to highlight why previously researched issues related to the topic were not addressed.

Examples of delimitating choices would be:

  • The key aims and objectives of your study,
  • The research questions that you address,
  • The variables of interest [i.e., the various factors and features of the phenomenon being studied],
  • The method(s) of investigation,
  • The time period your study covers, and
  • Any relevant alternative theoretical frameworks that could have been adopted.

Review each of these decisions. Not only do you clearly establish what you intend to accomplish in your research, but you should also include a declaration of what the study does not intend to cover. In the latter case, your exclusionary decisions should be based upon criteria understood as, "not interesting"; "not directly relevant"; “too problematic because..."; "not feasible," and the like. Make this reasoning explicit!

NOTE:   Delimitations refer to the initial choices made about the broader, overall design of your study and should not be confused with documenting the limitations of your study discovered after the research has been completed.

ANOTHER NOTE: Do not view delimitating statements as admitting to an inherent failing or shortcoming in your research. They are an accepted element of academic writing intended to keep the reader focused on the research problem by explicitly defining the conceptual boundaries and scope of your study. It addresses any critical questions in the reader's mind of, "Why the hell didn't the author examine this?"

III.  The Narrative Flow

Issues to keep in mind that will help the narrative flow in your introduction :

  • Your introduction should clearly identify the subject area of interest . A simple strategy to follow is to use key words from your title in the first few sentences of the introduction. This will help focus the introduction on the topic at the appropriate level and ensures that you get to the subject matter quickly without losing focus, or discussing information that is too general.
  • Establish context by providing a brief and balanced review of the pertinent published literature that is available on the subject. The key is to summarize for the reader what is known about the specific research problem before you did your analysis. This part of your introduction should not represent a comprehensive literature review--that comes next. It consists of a general review of the important, foundational research literature [with citations] that establishes a foundation for understanding key elements of the research problem. See the drop-down menu under this tab for " Background Information " regarding types of contexts.
  • Clearly state the hypothesis that you investigated . When you are first learning to write in this format it is okay, and actually preferable, to use a past statement like, "The purpose of this study was to...." or "We investigated three possible mechanisms to explain the...."
  • Why did you choose this kind of research study or design? Provide a clear statement of the rationale for your approach to the problem studied. This will usually follow your statement of purpose in the last paragraph of the introduction.

IV.  Engaging the Reader

A research problem in the social sciences can come across as dry and uninteresting to anyone unfamiliar with the topic . Therefore, one of the goals of your introduction is to make readers want to read your paper. Here are several strategies you can use to grab the reader's attention:

  • Open with a compelling story . Almost all research problems in the social sciences, no matter how obscure or esoteric , are really about the lives of people. Telling a story that humanizes an issue can help illuminate the significance of the problem and help the reader empathize with those affected by the condition being studied.
  • Include a strong quotation or a vivid, perhaps unexpected, anecdote . During your review of the literature, make note of any quotes or anecdotes that grab your attention because they can used in your introduction to highlight the research problem in a captivating way.
  • Pose a provocative or thought-provoking question . Your research problem should be framed by a set of questions to be addressed or hypotheses to be tested. However, a provocative question can be presented in the beginning of your introduction that challenges an existing assumption or compels the reader to consider an alternative viewpoint that helps establish the significance of your study. 
  • Describe a puzzling scenario or incongruity . This involves highlighting an interesting quandary concerning the research problem or describing contradictory findings from prior studies about a topic. Posing what is essentially an unresolved intellectual riddle about the problem can engage the reader's interest in the study.
  • Cite a stirring example or case study that illustrates why the research problem is important . Draw upon the findings of others to demonstrate the significance of the problem and to describe how your study builds upon or offers alternatives ways of investigating this prior research.

NOTE:   It is important that you choose only one of the suggested strategies for engaging your readers. This avoids giving an impression that your paper is more flash than substance and does not distract from the substance of your study.

Freedman, Leora  and Jerry Plotnick. Introductions and Conclusions. University College Writing Centre. University of Toronto; Introduction. The Structure, Format, Content, and Style of a Journal-Style Scientific Paper. Department of Biology. Bates College; Introductions. The Writing Center. University of North Carolina; Introductions. The Writer’s Handbook. Writing Center. University of Wisconsin, Madison; Introductions, Body Paragraphs, and Conclusions for an Argument Paper. The Writing Lab and The OWL. Purdue University; “Writing Introductions.” In Good Essay Writing: A Social Sciences Guide . Peter Redman. 4th edition. (London: Sage, 2011), pp. 63-70; Resources for Writers: Introduction Strategies. Program in Writing and Humanistic Studies. Massachusetts Institute of Technology; Sharpling, Gerald. Writing an Introduction. Centre for Applied Linguistics, University of Warwick; Samraj, B. “Introductions in Research Articles: Variations Across Disciplines.” English for Specific Purposes 21 (2002): 1–17; Swales, John and Christine B. Feak. Academic Writing for Graduate Students: Essential Skills and Tasks . 2nd edition. Ann Arbor, MI: University of Michigan Press, 2004 ; Writing Your Introduction. Department of English Writing Guide. George Mason University.

Writing Tip

Avoid the "Dictionary" Introduction

Giving the dictionary definition of words related to the research problem may appear appropriate because it is important to define specific terminology that readers may be unfamiliar with. However, anyone can look a word up in the dictionary and a general dictionary is not a particularly authoritative source because it doesn't take into account the context of your topic and doesn't offer particularly detailed information. Also, placed in the context of a particular discipline, a term or concept may have a different meaning than what is found in a general dictionary. If you feel that you must seek out an authoritative definition, use a subject specific dictionary or encyclopedia [e.g., if you are a sociology student, search for dictionaries of sociology]. A good database for obtaining definitive definitions of concepts or terms is Credo Reference .

Saba, Robert. The College Research Paper. Florida International University; Introductions. The Writing Center. University of North Carolina.

Another Writing Tip

When Do I Begin?

A common question asked at the start of any paper is, "Where should I begin?" An equally important question to ask yourself is, "When do I begin?" Research problems in the social sciences rarely rest in isolation from history. Therefore, it is important to lay a foundation for understanding the historical context underpinning the research problem. However, this information should be brief and succinct and begin at a point in time that illustrates the study's overall importance. For example, a study that investigates coffee cultivation and export in West Africa as a key stimulus for local economic growth needs to describe the beginning of exporting coffee in the region and establishing why economic growth is important. You do not need to give a long historical explanation about coffee exports in Africa. If a research problem requires a substantial exploration of the historical context, do this in the literature review section. In your introduction, make note of this as part of the "roadmap" [see below] that you use to describe the organization of your paper.

Introductions. The Writing Center. University of North Carolina; “Writing Introductions.” In Good Essay Writing: A Social Sciences Guide . Peter Redman. 4th edition. (London: Sage, 2011), pp. 63-70.

Yet Another Writing Tip

Always End with a Roadmap

The final paragraph or sentences of your introduction should forecast your main arguments and conclusions and provide a brief description of the rest of the paper [the "roadmap"] that let's the reader know where you are going and what to expect. A roadmap is important because it helps the reader place the research problem within the context of their own perspectives about the topic. In addition, concluding your introduction with an explicit roadmap tells the reader that you have a clear understanding of the structural purpose of your paper. In this way, the roadmap acts as a type of promise to yourself and to your readers that you will follow a consistent and coherent approach to addressing the topic of inquiry. Refer to it often to help keep your writing focused and organized.

Cassuto, Leonard. “On the Dissertation: How to Write the Introduction.” The Chronicle of Higher Education , May 28, 2018; Radich, Michael. A Student's Guide to Writing in East Asian Studies . (Cambridge, MA: Harvard University Writing n. d.), pp. 35-37.

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How to Write a Research Introduction

Last Updated: December 6, 2023 Fact Checked

This article was co-authored by Megan Morgan, PhD . Megan Morgan is a Graduate Program Academic Advisor in the School of Public & International Affairs at the University of Georgia. She earned her PhD in English from the University of Georgia in 2015. There are 7 references cited in this article, which can be found at the bottom of the page. This article has been fact-checked, ensuring the accuracy of any cited facts and confirming the authority of its sources. This article has been viewed 2,653,642 times.

The introduction to a research paper can be the most challenging part of the paper to write. The length of the introduction will vary depending on the type of research paper you are writing. An introduction should announce your topic, provide context and a rationale for your work, before stating your research questions and hypothesis. Well-written introductions set the tone for the paper, catch the reader's interest, and communicate the hypothesis or thesis statement.

Introducing the Topic of the Paper

Step 1 Announce your research topic.

  • In scientific papers this is sometimes known as an "inverted triangle", where you start with the broadest material at the start, before zooming in on the specifics. [2] X Research source
  • The sentence "Throughout the 20th century, our views of life on other planets have drastically changed" introduces a topic, but does so in broad terms.
  • It provides the reader with an indication of the content of the essay and encourages them to read on.

Step 2 Consider referring to key words.

  • For example, if you were writing a paper about the behaviour of mice when exposed to a particular substance, you would include the word "mice", and the scientific name of the relevant compound in the first sentences.
  • If you were writing a history paper about the impact of the First World War on gender relations in Britain, you should mention those key words in your first few lines.

Step 3 Define any key terms or concepts.

  • This is especially important if you are attempting to develop a new conceptualization that uses language and terminology your readers may be unfamiliar with.

Step 4 Introduce the topic through an anecdote or quotation.

  • If you use an anecdote ensure that is short and highly relevant for your research. It has to function in the same way as an alternative opening, namely to announce the topic of your research paper to your reader.
  • For example, if you were writing a sociology paper about re-offending rates among young offenders, you could include a brief story of one person whose story reflects and introduces your topic.
  • This kind of approach is generally not appropriate for the introduction to a natural or physical sciences research paper where the writing conventions are different.

Establishing the Context for Your Paper

Step 1 Include a brief literature review.

  • It is important to be concise in the introduction, so provide an overview on recent developments in the primary research rather than a lengthy discussion.
  • You can follow the "inverted triangle" principle to focus in from the broader themes to those to which you are making a direct contribution with your paper.
  • A strong literature review presents important background information to your own research and indicates the importance of the field.

Step 2 Use the literature to focus in on your contribution.

  • By making clear reference to existing work you can demonstrate explicitly the specific contribution you are making to move the field forward.
  • You can identify a gap in the existing scholarship and explain how you are addressing it and moving understanding forward.

Step 3 Elaborate on the rationale of your paper.

  • For example, if you are writing a scientific paper you could stress the merits of the experimental approach or models you have used.
  • Stress what is novel in your research and the significance of your new approach, but don't give too much detail in the introduction.
  • A stated rationale could be something like: "the study evaluates the previously unknown anti-inflammatory effects of a topical compound in order to evaluate its potential clinical uses".

Specifying Your Research Questions and Hypothesis

Step 1 State your research questions.

  • The research question or questions generally come towards the end of the introduction, and should be concise and closely focused.
  • The research question might recall some of the key words established in the first few sentences and the title of your paper.
  • An example of a research question could be "what were the consequences of the North American Free Trade Agreement on the Mexican export economy?"
  • This could be honed further to be specific by referring to a particular element of the Free Trade Agreement and the impact on a particular industry in Mexico, such as clothing manufacture.
  • A good research question should shape a problem into a testable hypothesis.

Step 2 Indicate your hypothesis.

  • If possible try to avoid using the word "hypothesis" and rather make this implicit in your writing. This can make your writing appear less formulaic.
  • In a scientific paper, giving a clear one-sentence overview of your results and their relation to your hypothesis makes the information clear and accessible. [10] X Trustworthy Source PubMed Central Journal archive from the U.S. National Institutes of Health Go to source
  • An example of a hypothesis could be "mice deprived of food for the duration of the study were expected to become more lethargic than those fed normally".

Step 3 Outline the structure of your paper.

  • This is not always necessary and you should pay attention to the writing conventions in your discipline.
  • In a natural sciences paper, for example, there is a fairly rigid structure which you will be following.
  • A humanities or social science paper will most likely present more opportunities to deviate in how you structure your paper.

Research Introduction Help

length of introduction in research paper

Community Q&A

Community Answer

  • Use your research papers' outline to help you decide what information to include when writing an introduction. Thanks Helpful 0 Not Helpful 1
  • Consider drafting your introduction after you have already completed the rest of your research paper. Writing introductions last can help ensure that you don't leave out any major points. Thanks Helpful 0 Not Helpful 0

length of introduction in research paper

  • Avoid emotional or sensational introductions; these can create distrust in the reader. Thanks Helpful 50 Not Helpful 12
  • Generally avoid using personal pronouns in your introduction, such as "I," "me," "we," "us," "my," "mine," or "our." Thanks Helpful 31 Not Helpful 7
  • Don't overwhelm the reader with an over-abundance of information. Keep the introduction as concise as possible by saving specific details for the body of your paper. Thanks Helpful 24 Not Helpful 14

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Publish a Research Paper

  • ↑ https://library.sacredheart.edu/c.php?g=29803&p=185916
  • ↑ https://www.aresearchguide.com/inverted-pyramid-structure-in-writing.html
  • ↑ https://libguides.usc.edu/writingguide/introduction
  • ↑ https://writing.wisc.edu/Handbook/PlanResearchPaper.html
  • ↑ https://dept.writing.wisc.edu/wac/writing-an-introduction-for-a-scientific-paper/
  • ↑ https://writing.wisc.edu/handbook/assignments/planresearchpaper/
  • ↑ http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3178846/

About This Article

Megan Morgan, PhD

To introduce your research paper, use the first 1-2 sentences to describe your general topic, such as “women in World War I.” Include and define keywords, such as “gender relations,” to show your reader where you’re going. Mention previous research into the topic with a phrase like, “Others have studied…”, then transition into what your contribution will be and why it’s necessary. Finally, state the questions that your paper will address and propose your “answer” to them as your thesis statement. For more information from our English Ph.D. co-author about how to craft a strong hypothesis and thesis, keep reading! Did this summary help you? Yes No

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COMMENTS

  1. Writing a Research Paper Introduction

    The introduction to a research paper is where you set up your topic and approach for the reader. It has several key goals: Present your topic and get the reader interested. Provide background or summarize existing research. Position your own approach. Detail your specific research problem and problem statement.

  2. How Long Should the Introduction of a Research Paper Be? Data

    From these data, we can conclude that most research papers have a 3 to 5 paragraph introductions (consisting of 15 to 28 sentences). If you are interested, here’s the link to the PubMed article that had the longest introduction of 9,776 words, 426 sentences, and 196 paragraphs!

  3. Research Paper Introduction

    Research paper introduction is the first section of a research paper that provides an overview of the study, its purpose, and the research question (s) or hypothesis (es) being investigated. It typically includes background information about the topic, a review of previous research in the field, and a statement of the research objectives.

  4. How to Write a Research Paper Introduction

    How long should a research paper introduction be? There are no firm rules on how long a research paper introduction should be. The only guideline is that the length of the introduction should be commensurate with the length of the entire paper.

  5. How to Write an Introduction for a Research Paper

    Your introduction should be about the same length as any other paragraph in your research paper. Let the content—what you have to say—dictate the length. Your Opening Paragraphs.

  6. 4. The Introduction

    According to Reyes, there are three overarching goals of a good introduction: 1) ensure that you summarize prior studies about the topic in a manner that lays a foundation for understanding the research problem; 2) explain how your study specifically addresses gaps in the literature, insufficient consideration of the topic, or other deficiency i...

  7. How to Write a Research Introduction: 10 Steps (with Pictures)

    The length of the introduction will vary depending on the type of research paper you are writing. An introduction should announce your topic, provide context and a rationale for your work, before stating your research questions and hypothesis.

  8. How to Write a Thesis or Dissertation Introduction

    Revised on November 21, 2023. The introduction is the first section of your thesis or dissertation, appearing right after the table of contents. Your introduction draws your reader in, setting the stage for your research with a clear focus, purpose, and direction on a relevant topic. Your introduction should include: