How to Write a Research Paper Introduction

Readers decide in the first paragraph or two whether a research paper is worth their attention, and markers form an early impression of how well you understand your topic. A good introduction does not wander through general statements about society. It moves quickly from a broad context to a specific problem, shows what earlier research has and has not answered, and ends with a clear statement of what your paper does.

This guide covers the structure of an effective introduction, the widely taught CARS model, how the introduction differs between argumentative and empirical papers, how long it should be and how to avoid the habits that make introductions weak.

What an Introduction Must Do

Whatever your discipline, the introduction does four jobs:

1. Establish the topic and its importance: why should anyone care about this area?
2. Summarise what is already known: a brief view of the relevant research, not a full literature review.
3. Identify the gap or problem: what is missing, disputed or unresolved?
4. State what your paper does: your research question, aim, hypothesis or thesis, and often how the paper is organised.

The CARS Model

Linguist John Swales studied how published research introductions are built and described a pattern he called Create a Research Space (CARS). It has three "moves", and it remains one of the most useful ways to plan an introduction.

The model works because it creates a logical need for your paper. By the time readers reach your aim, they already understand why it matters.

Step 1: Open With Focused Context

Start close to your topic. Broad openings such as "Since the dawn of time" or "In today's society" waste the reader's attention and signal that the writer has not yet found their focus.

• Weak: "Technology is a very important part of modern life."
• Better: "Universities have rapidly expanded online assessment since 2020, and many now use remote proctoring software to discourage cheating."

Good openings include a specific trend, a significant statistic from a credible source, a recent policy change or a well-defined problem. Cite any fact you use.

Step 2: Summarise What Is Known

Briefly show the main findings or positions in the existing research. In a short paper this may be three or four sentences; in a longer empirical paper it may be a few paragraphs. Synthesise rather than list: group sources by what they found or argued.

Step 3: Identify the Gap

The gap is the turning point of the introduction. It shows why your paper is needed. Gaps take several forms:

• Something has not been studied: a population, setting or time period.
• Findings conflict: studies disagree and the reason is unclear.
• A method has limitations: earlier work relied on small samples or self-report.
• A practical problem remains: evidence exists but has not been applied in a particular context.
• An argument has been overlooked (common in humanities papers): a text or issue has not been read from a particular angle.

Be honest about the gap. Claiming that "no research exists" on a topic is risky and often wrong. "Few studies have examined..." or "research has rarely focused on..." is usually more accurate.

Step 4: State Your Aim, Question or Thesis

End the introduction with a clear statement of what your paper does. The form depends on the paper type.

Many papers then add a sentence or two previewing the structure: "The paper first reviews..., then presents..., and finally discusses...". This roadmap is common in longer papers and less necessary in short ones.

Annotated Example

Each sentence does one job, and the paragraph moves steadily from broad to specific.

How Long Should an Introduction Be?

About a tenth of the total word count is a common rule of thumb. Your assignment and discipline may vary.

Introductions by Discipline

• Sciences and health: concise context, research findings with citations, a clear gap, then aims and hypotheses. Often follows the IMRaD structure.
• Social sciences: similar, often with a theoretical framework introduced briefly.
• Humanities: may open with a quotation, scene or interpretive problem, then state a thesis about a text or issue. Literature is engaged throughout the paper rather than only in the introduction.
• Business: often frames a practical problem facing organisations before linking it to research.

Write It Last (or Revise It Last)

Many experienced writers draft a rough introduction to guide their thinking, then rewrite it after finishing the paper. Your argument often sharpens as you write, and an introduction written first may promise something the paper no longer delivers. Before submitting, check that every claim the introduction makes is fulfilled in the body and conclusion.

Common Mistakes

• Starting too broadly with generic statements about society or history.
• Turning the introduction into a full literature review. Keep detailed discussion for the review section.
• No clear gap, so the reader cannot see why the paper is needed.
• A vague aim such as "this paper will discuss proctoring".
• Uncited facts and statistics.
• Announcing instead of stating: "In this paper I will talk about..." is weaker than stating the aim or argument directly.
• Mismatch with the paper: the introduction promises something the body does not deliver.

Checklist

• The opening is specific to the topic, not a general statement.
• Key existing research is synthesised and cited.
• The gap or problem is clear and accurately stated.
• The aim, research question or thesis is specific.
• Hypotheses are stated where the paper type requires them.
• The length suits the paper.
• Everything promised is delivered in the paper.