Writing a Research Paper Introduction Step by Step

Reviewers often decide on the first page whether a paper deserves their full attention, and that page is your introduction. A strong introduction shows why the topic matters, what is already known, what is missing, and exactly how your study fills that gap. A weak one wanders through general background, lists citations without an argument, and leaves the research question to the last line, or never states it at all. This guide gives you two proven structures, a method for each part, and a worked example you can adapt to your own field.

What a research paper introduction must do

The introduction is an argument, not a summary. By its last line a reader should be able to answer five questions:

1. What is the problem, and why does it matter?
2. What does existing research already show?
3. What is still missing, uncertain or contradictory?
4. What exactly did this study set out to do?
5. What will the reader gain from this paper?

Each answer sets up a later section. The gap justifies the methods, the research questions define what the results must report, and the stated contribution is what the discussion must deliver. If the introduction promises something the results never address, reviewers notice at once.

In a typical IMRaD article the introduction also carries a compressed, selective literature review; theses and some social science journals add a separate review or framework section instead. See Writing an IMRaD Paper Journals Accept for the overall structure.

The funnel structure: from broad to narrow

The simplest way to organise an introduction is as a funnel. Start with a statement any reader in your field accepts, and narrow paragraph by paragraph until you reach your specific question.

• Context (paragraph 1): establish the topic and its importance with one or two well-sourced facts, such as prevalence, cost, policy relevance or theoretical significance.
• What is known (paragraphs 2–3): summarise the most relevant findings, grouped by theme rather than study by study.
• The gap (paragraph 4): show where current knowledge stops.
• The study (final paragraph): state the aim, research questions or hypotheses and the contribution.

The usual failure is a funnel mouth that is too wide. “Since ancient times, education has been central to human civilisation” wastes the reader’s most attentive moment. A useful test: your first sentence should make sense only in a paper on your general topic, not in any paper at all. Give each paragraph one job, stated in its first sentence.

The CARS model: three rhetorical moves

Linguist John Swales analysed research article introductions and described a recurring pattern he called CARS, or Create a Research Space (Genre Analysis, 1990). It refines the funnel into three “moves”.

The model describes common practice rather than a rule, and disciplines apply it differently: medical introductions are short and end with a one-sentence aim, while humanities introductions may cycle between moves 1 and 2 before settling on the argument. What every good introduction shares is a clearly signalled Move 2. Without a niche, the study has no reason to exist.

Writing the background without a mini literature review

The background (Move 1) should be selective and purposeful. Its job is to bring the reader to your gap by the shortest credible route, not to display everything you have read.

• Group studies by finding. Write “Surveys of urban commuters consistently report…” with three citations, instead of three sentences that each begin with an author’s name.
• Combine foundational and recent sources. Cite the defining studies and the latest evidence; skip the repetitive middle.
• Show tension, not only agreement. Conflicting findings, differing methods and limited samples are what set up your gap.
• Define key terms early, especially constructs with competing definitions.
• Stay on the path. A paragraph that does not lead toward your question belongs in the discussion or nowhere.

If your study needs a full theoretical framework, give it a separate section. For synthesis techniques, see Literature Review in 2026: A Step-by-Step Method and Literature Reviews That Synthesise, Not List.

Stating the research gap precisely

The gap is the hinge of the introduction. “There is a lack of research in this area” is one of the most common phrases reviewers criticise, because it is rarely true and impossible to check. A precise gap names what is missing and why it matters. Gaps usually take one of these forms:

• Population or context: evidence exists, but not for this group, region or sector.
• Method: earlier studies relied on small samples, self-report or cross-sectional data.
• Contradiction: studies disagree and the reason is unclear.
• Time: a new policy, technology or event means older findings may no longer hold.
• Theory: a theory has not been tested in this setting, or two theories predict different outcomes.

Avoid absolutes such as “no study has ever…”; a reviewer needs only one counter-example. “Few studies have…” or “evidence is limited for…” is safer, after a genuine search.

Aims, objectives, research questions and hypotheses

The introduction ends by stating precisely what the study did. Four related terms are often blurred:

Not every paper needs all four. A confirmatory quantitative study usually states an aim and hypotheses; an exploratory or qualitative study states an aim and research questions. What matters is that each question or hypothesis is answered in the results, in the same order and wording; numbering them (RQ1, H1) helps. Prefer checkable verbs such as measure, compare or identify to “understand”.

Writing a clear contribution statement

Editors want to know quickly what your paper adds. A contribution statement of one to three sentences near the end of the introduction answers that directly, and it is stronger when it names the type of contribution: empirical (new data, population or setting), methodological (a new instrument, model or validation), theoretical (testing or extending a theory) or practical (evidence for a policy or practice decision).

Computer science and engineering papers often use a bulleted contributions list and a short roadmap (“Section 2 reviews…”); in IMRaD papers a roadmap is unnecessary. In every field, claim no more than the results will show.

How long should the introduction be?

Length depends on discipline, article type and journal, but some broad patterns hold:

• Clinical and health sciences: often three or four paragraphs, frequently 300–600 words.
• Natural sciences and engineering: commonly 500–1,000 words.
• Social sciences and management: often 600–1,200 words, especially when theory is developed in the introduction.
• Humanities: variable, and sometimes several pages.

As a working rule, the introduction of an empirical article is around 10–15% of the total length. If yours nears a quarter of the paper, it probably contains review material that belongs elsewhere. The most reliable benchmark is to read five recent articles of the same type in your target journal and note how long their introductions are and how they end. If you submit to JMVRA, the publication guidelines set out the manuscript structure the editors expect.

Using citations and tense in the introduction

The introduction usually has the densest citations in the paper, so citation habits shape how reviewers judge your scholarship. The ICMJE recommendations, written for medical journals but widely applicable, advise citing only directly pertinent references and keeping data and conclusions from the present study out of the introduction.

• Cite claims, not decoration. Facts about prevalence, trends or prior findings need a source.
• Avoid citation dumps. Ten references after one sentence suggests you have not read them closely; cite the two or three most relevant, or a recent review.
• Prefer primary sources and keep self-citation proportionate.

A common tense convention is present tense for established knowledge (“Air pollution is associated with…”), past tense for what particular studies did (“Rao and colleagues reported…”) and present perfect for research trends (“Several studies have examined…”). Apply your target journal’s citation style consistently; Citation Styles Compared summarises the main ones.

A worked example, paragraph by paragraph

The illustrative example below uses placeholder citations and shows how the funnel and the CARS moves fit into a compact four-part introduction.

The opening is field-specific, the background groups studies by finding, the gap names a population and a missing distinction, and the aim answers that gap with two numbered questions.

Common introduction mistakes

1. Starting too broad, with history, globalisation or “today’s fast-changing world”.
2. A list instead of an argument: one study per sentence, with no connections drawn.
3. A missing or hidden gap, so the reader never learns why the study was needed.
4. An aim that does not match the gap, such as a gap about rural students and an aim about all students.
5. Methods and results in the introduction. A one-line preview of the main finding is accepted in some fields, but procedures and statistics belong in later sections.
6. Overclaiming significance in ways the discussion cannot support.
7. Recycled text from a thesis or earlier paper, a frequent cause of high similarity scores. JMVRA expects similarity below 15%, and reused background paragraphs push that figure up quickly.

For the wider picture, see Why Manuscripts Get Rejected and What to Do, and Turning a PhD Thesis Into Journal Articles if you are adapting a thesis chapter.

Quick Checklist

1. Specific openingFirst sentence fits your field, not every paper
2. Grouped backgroundStudies synthesised by theme, not listed one by one
3. Precise gapNames the missing population, method or evidence
4. Matching aimAim and questions answer the gap exactly
5. Contribution statedOne to three sentences on what the paper adds
6. Proportionate lengthAbout 10–15% of the paper; journal norms checked

Questions Researchers Often Ask

In Summary

An effective introduction moves the reader from a recognisable problem to a precise question in a few well-built paragraphs. Use the funnel to order your material and the CARS moves to check that each part does its job: establish the territory, show the niche, then occupy it with a clear aim, research questions or hypotheses, and an honest contribution statement. Keep the background selective, the gap specific, the citations purposeful and the length in line with your target journal. Then revisit the introduction once the discussion is written, so that what you promise at the start is exactly what the paper delivers.

References and Sources

• ICMJE — Recommendations for the Conduct, Reporting, Editing and Publication of Scholarly Work
• EQUATOR Network — Reporting guidelines for health research
• APA Style — Official guidance on writing and formatting