How to Write a Research Paper Introduction: Funnel Approach with Examples

Start Broad, Narrow Down, State Your Question

The funnel approach is one of the most reliable structural frameworks for writing a research paper introduction. It works like a traffic funnel: you start with broad context that almost anyone in your field can follow, then gradually narrow your focus until you arrive at your specific research question. This method — formally known as the CARS model, developed by linguist John Swales in 1990 — is widely taught in graduate writing programs and used by experienced journal authors. When executed well, it guides your reader from “Why should I care?” to “This matters because it fills a clear gap” in just a few paragraphs.

This guide walks you through each of the five parts of a funnel introduction with concrete, worked examples. You’ll also learn discipline-specific nuances (what works in social sciences often doesn’t work in biomedical sciences), ready-to-use gap statement phrases, and why your introduction should actually be written after you finish your Discussion section — a counterintuitive tip that most student guides don’t mention.

• The funnel is an inverted triangle: start broad (hook/context), narrow through background, identify a gap, then state your specific aim or research question.
• The funnel belongs to empirical research papers, not essays: Harvard’s College Writing Center explicitly warns against using this structure for undergraduate essays.
• Gap statements follow predictable patterns: Use phrase templates like “Although X has been studied, insufficient attention has been paid to Y” to make the pivot from background to gap seamless.
• Different disciplines expect different hooks: Social sciences favor societal trends and statistics; biomedical fields use clinical burden data; physical sciences lean toward applied or technological drivers.
• Your introduction should funnel down; your Discussion should funnel back up: Together they form the “hourglass structure” — a widely taught concept that connects your opening to your conclusions.

What Is the Funnel Approach?

The funnel approach (also called the “narrowing” or “inverted triangle” structure) is a method of building a research paper introduction that moves from general knowledge to your specific contribution. It looks — literally — like a funnel: wide at the top, narrow at the bottom.

The model was formalized by linguist John Swales in 1990 as the CARS model (“Create a Research Space”). Swales identified three rhetorical moves that journal authors use to establish a niche for their work: establishing the research territory, establishing a niche (the gap), and occupying the niche (your contribution). This framework has been adopted across disciplines because it works — it mirrors how researchers actually think about their work.

The funnel typically includes five components:

1. Hook / Broad Context: A statement that situates the reader in the general field.
2. Narrower Background: Scholarly context with citations to existing research.
3. Gap Statement: Identification of what’s missing, contradictory, or unknown.
4. Purpose / Research Question: Your specific aim, hypothesis, or research question.
5. Roadmap (optional): A brief outline of the paper’s structure.

A critical warning from Harvard’s College Writing Center: “Avoid writing a ‘funnel’ introduction in which you begin with a very broad statement about a topic and move to a narrow statement about that topic.” Harvard explicitly advises against this approach — but not because the funnel itself is flawed. They’re warning that this structure is designed for empirical research papers and journal articles, not for undergraduate essays or argumentative papers. If your assignment is an essay, a different structure (such as a thesis-driven paragraph) is likely more appropriate. Know your assignment type before applying the funnel.

The funnel approach targets approximately 10% of your total paper length — about 500 to 1,000 words for a journal article, or 2-3 paragraphs for shorter papers. This keeps the introduction concise while providing enough context to justify your research.

The 5 Parts of a Funnel Introduction (with Worked Examples)

Now let’s walk through each component with concrete examples. The narrowing process below shows how to move from a broad topic to a specific research question in three successive steps.

Part 1: Broad Context / Hook

Start with a statement that almost anyone in your field would agree with. This doesn’t need to be surprising — it needs to be broadly relevant.

Worked Example:

“Climate change is accelerating urban environmental challenges worldwide. From flooding to extreme heat events, cities across the globe are experiencing unprecedented stress on infrastructure and public health.”

This opening is broad but focused enough that a reader understands the general territory. You’re not asking the reader to accept a controversial claim — you’re situating them in a shared understanding of the field.

Tips for hooks:

• Use a broadly accepted fact, trend, or statistic
• Avoid starting with a provocative question unless your discipline expects one
• Keep it to one or two sentences
• The Golden Thread emphasizes “broad, but not too broad“: if your hook discusses humanity’s relationship with the Earth, you’re being too broad. If it discusses urban environmental stress, you’re in the right range

Part 2: Narrower Background

Now narrow the focus. This is where you introduce the scholarly literature — but carefully. Unlike a full literature review, the introduction should only provide essential context.

Worked Example:

“Urban heat island effects — where cities become significantly warmer than surrounding rural areas — have been documented across dozens of studies (Li et al., 2019; Rozo & Caset, 2021). Research has linked these effects to increased energy consumption, respiratory illness, and disproportionate heat-related mortality among vulnerable populations (Bárcena & Ojeda-Bannigan, 2021). The literature converges on the finding that urban design, including vegetation cover and surface materials, plays a key role in mitigating heat stress.”

This paragraph narrows from “climate change in cities” to “urban heat islands” with specific citations. Notice the citation density: two citations per claim, not a wall of 10 references. As Editage warns, “stacking citations without differentiating them” (e.g., “many studies have found X (Smith, 2018; Jones, 2019; Lee, 2020; Chen, 2021; Kumar, 2022)”) is a common beginner mistake. Break broad claims into sub-claims, each supported by its own citation cluster.

Part 3: The Gap Statement

This is the single most important part of your introduction. You must clearly identify what is missing, unknown, or contradictory in existing research. This gap justifies your study.

Worked Example:

“However, most of these studies focus on high-income urban neighborhoods. Very little research has examined how low-income residents experience or respond to heat stress, or whether community-led coping strategies can meaningfully reduce health risks in these areas.”

The pivot from background to gap is signaled by the word “however.” This transition is critical: it tells the reader that you’ve moved from what we know to what we don’t know.

Types of gaps you can identify:

• Methodological gap: “Previous studies have primarily used self-report measures, which may not capture the full range of online behaviors.”
• Population gap: “Most research has focused on Western, educated populations, leaving significant gaps in understanding effects across different cultural contexts.”
• Temporal gap: “While recent studies have examined the impact of X, few have investigated how these effects change over time.”
• Theoretical gap: “Existing theories of technology use fail to account for the unique affordances of different platforms.”
• Contradictory evidence gap: “Findings remain inconsistent, suggesting that the effect may depend on a moderating variable.”

Part 4: Research Purpose / Question

Now state what your study will do. Be specific and measurable. This is the narrowest point of the funnel.

Worked Example:

“This study evaluates adaptive responses to heat stress among residents in low-income neighborhoods in a major U.S. city. Specifically, we examine whether community-led coping strategies — such as neighborhood shade gardens and shared cooling centers — reduce heat-related illness symptoms. We hypothesize that neighborhoods with organized coping strategies will show lower rates of respiratory and cardiovascular complaints compared to neighborhoods without such interventions.”

This purpose statement is direct, specific, and follows logically from the gap. The reader now understands exactly what the paper does.

Part 5: Roadmap (Optional)

Some disciplines prefer including a brief outline of the paper’s structure. This is particularly helpful for longer papers or those with multiple sections. The roadmap is optional — check your discipline’s conventions.

Worked Example:

“The remainder of this paper first reviews relevant literature on urban heat islands, then presents our research methods and data, followed by results, discussion, and conclusions.”

Discipline-Specific Nuances

Not all disciplines use the funnel the same way. The following table summarizes how hook styles, citation conventions, gap framing, and roadmap use differ across three common disciplines.

Note: The above table is adapted from discipline-specific conventions documented by Editage (2026). Always check your target journal’s author guidelines for field-specific expectations. UCI Libraries’ scientific writing guide also provides discipline-specific introduction conventions for science papers (UCI Libraries, Scientific Writing: Introduction).

Common Mistakes Students Make with Funnel Introductions

Even diligent students can undermine their introductions. Here are the most common errors and how to avoid them.

Mistake 1: Writing a Funnel When You Shouldn’t

The problem: The funnel approach is designed for empirical research papers and journal articles. Harvard’s College Writing Center warns explicitly against using it for undergraduate essays or argumentative papers. If your assignment is an essay, you’ll likely need a thesis-driven structure instead.

The fix: Before drafting, identify your assignment type. Is it an empirical paper? A thesis essay? A course reflection? Use the funnel only when your assignment calls for it.

Mistake 2: Starting Too Narrowly

The problem: Jumping straight into your specific research question without providing broader context. This confuses readers about why your study matters.

The fix: Use the funnel. Start broad, then gradually narrow. Don’t open with “I am studying urban heat islands and their effect on low-income neighborhoods” — open with the broader context of climate and urban environments.

Mistake 3: Citation Stacking

The problem: Including too many citations in one sentence without differentiating them. Example: “Multiple studies have found that X affects Y (Smith, 2018; Jones, 2019; Lee, 2020; Chen, 2021; Kumar, 2022; Wang, 2023).” This overwhelms readers and makes your writing hard to parse.

The fix: Break broad claims into sub-claims, each supported by its own citation cluster. Group similar findings and attribute them specifically.

Mistake 4: Vague Gap Statements

The problem: Saying “there is a gap in the literature” without specifying what the gap is. This tells the reader nothing about why your study is necessary.

The fix: Be specific. Name the population, method, or theory that’s understudied. Use the gap templates provided in the next section.

Mistake 5: Overly Long Introductions

The problem: Treating the introduction as a comprehensive literature review. Writing 5 pages of background before reaching your research question.

The fix: Target approximately 10% of your total paper length. Save detailed literature reviews for a dedicated section. The introduction should provide just enough context to make your research question intelligible.

See our literature review guide for the step-by-step process of building a full literature review — which belongs in the dedicated section, not the introduction.

How the Funnel Connects to the Rest of Your Paper (The Hourglass Structure)

Here’s a concept you won’t find in many student guides: the funnel approach doesn’t just shape your introduction. It shapes your entire paper. This is known as the hourglass structure.

The Introduction funnels down (broad context → specific research question).

The Discussion funnels back up (specific findings → broader significance).

Together, they form an hourglass — wide at the top (the broad opening), narrow in the middle (your methods and results), and wide again at the bottom (your conclusions and implications). This structure is widely taught in graduate programs and discussed by CASRAI (NISO) as a best practice for scientific writing.

Why this matters: When you write the introduction first — before your Methods, Results, and Discussion — you risk creating a funnel that doesn’t match the paper you actually wrote. That’s why experienced researchers recommend writing the introduction last, or revising it extensively after completing your research. This ensures the funnel actually matches the paper you wrote, not the one you imagined.

Your Discussion section should effectively reverse the funnel. If your introduction narrows from “global climate change” to “heat stress in low-income neighborhoods,” your Discussion should widen back from “our specific findings” to “what this means for urban planning globally.” Our guide on writing research paper conclusions covers this reverse-funnel approach in detail.

For guidance on how to frame your research methods and results, see our methodology selection guide and our results section guide.

Gap Statement Phrases You Can Copy and Adapt

Transitioning from background to gap is where many students struggle. The good news: gap statements follow predictable, formulaic patterns. Below are six templates from Editage that you can copy and adapt.

1. “Although X has been studied in detail, insufficient attention has been paid to Y.” — Use when the literature on X is strong but Y remains underexplored.
2. “While existing research focuses on X, it remains unclear whether …” — Use when the literature addresses one thing but leaves another unanswered.
3. “However, little is known about how …” — Use when the phenomenon is understudied in a specific context or population.
4. “Despite these advances, the question of X remains open.” — Use when progress has been made but fundamental questions persist.
5. “Yet, critical questions persist regarding …” — Use when there are competing theories or contradictory findings.
6. “While previous studies have examined X, they have primarily focused on Y, leaving a gap in understanding Z.” — Use when you’re extending an existing line of research to a new population, context, or method.

These phrases are widely used in published papers. You can adapt the bolded placeholders to match your research. For a deeper look at gap identification, see Scribbr’s guide on writing research paper introductions.

Finding and Defining Your Gap

Identifying a genuine research gap — not just claiming one exists — requires reading the literature critically. Our 9-step literature review process for PhD students explains how to identify gaps systematically. If you’re conducting a systematic review, see our systematic literature review guide for PRISMA-compliant search strategies.

Once you’ve identified your gap, the next step is formulating a clear research question or hypothesis. Our hypothesis writing guide walks you through crafting testable predictions that flow directly from your gap statement.

Build the Funnel, Then Reverse It

The funnel approach gives you a reliable scaffold for writing a research paper introduction. Start broad, narrow through background, identify a clear gap, and state your specific aim. Use discipline-specific conventions to tailor your hook and citation style. And remember: the funnel doesn’t end at your introduction — it reverses in your Discussion section, forming the hourglass structure that ties your entire paper together.

Your next steps:

1. Identify your assignment type (empirical paper vs. essay) — use the funnel only when appropriate.
2. Draft a broad hook, then narrow through two levels of background.
3. Write your gap statement using one of the templates above.
4. State your purpose clearly and specifically.
5. Add a roadmap if your discipline expects one.
6. Write the introduction last, or revise it after completing your Discussion — this is the single most impactful revision you can make.

For a comprehensive pre-submission review, use our pre-submission checklist for research papers to catch common errors before you submit.

Need expert help? If you’d rather have a professional academic writer craft your introduction — or your entire research paper — visit our order page to get started. Our team of advanced writers holds Master’s and Ph.D. degrees and can deliver custom-written, plagiarism-free papers tailored to your topic and academic level.

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Additional reading: For understanding how to frame and analyze your research data, see our data analysis section guide. For guidance on addressing study limitations transparently, see our limitations writing guide.

Need expert help? Our professional academic writers can craft a custom research paper introduction — or an entire paper — tailored to your topic and academic level. Get a free quote today.