Linda Nyanchoka and colleagues reviewed 139 papers on how health researchers identify research gaps. They found 12 definitions of the term and no single method for identifying a gap.
The definitions vary, but the fundamental question is simpler. Adam Grant and Timothy Pollock, writing for authors at the Academy of Management Journal, found that strong introductions explain what is still unknown.
That unknown is the research gap.
New researchers often replace the gap with a broad topic statement:
Little research has examined sleep and exam scores.
This sentence tells us the research area. It does not tell us what earlier studies found or what they failed to answer.
A clearer research gap answers this question:
What have previous studies not established that this study can address?
The answer needs to be specific enough for one study to examine and supported by the published research you cite.
Key takeaways
- A research gap states what previous research has not answered.
- A topic, research problem, gap, and contribution have different purposes.
- The gap often appears in the abstract and introduction.
- A clear gap explains what previous studies found and what remains unknown.
- The study design needs to address the gap stated in the introduction.
What is a research gap?
A research gap is a question, population, measure, comparison, or explanation that previous studies have not resolved.
The gap needs to exist in the published research, not just in the papers you found. It also needs to be narrow enough for the current study to address.
John Swales describes this part of the introduction as establishing a research space. The author explains what is already known and then identifies what remains unanswered.
Compare these two statements:
Researchers need to conduct more studies on sleep and exam scores.
This is too broad. It does not identify the missing knowledge.
Now consider:
Previous studies measured sleep on the night before an exam, but they have not established whether the same association appears when sleep is measured across the full week.
This version tells the reader exactly what is still unknown.
Karen Robinson, Ian Saldanha, and Naomi McKoy describe several reasons a gap can exist in their framework for identifying research gaps. Limited, inconsistent, biased, or otherwise inadequate evidence may exist, preventing it from answering the question.
The research gap is closely connected to the research contribution, but they are not the same. The gap explains what previous research has not answered. The contribution explains what the new study adds after addressing that question.
Suppose earlier studies measured sleep on the night before an exam, but they did not examine average sleep across a full week. That is the gap.
If a new study finds that the relationship between short sleep and lower exam scores remains when sleep is measured across the week, that result can become part of the contribution.
The gap explains what was unknown. The contribution explains what was learned.
How is a research gap different from a topic or a problem?
A topic, research problem, research gap, and contribution often appear close together in an introduction. They are easy to confuse because they refer to the same study, but each has a different purpose.
A topic tells the reader what the study is about.
A problem explains the issue that makes the topic important.
A research gap states what previous research has not answered.
A contribution explains what the new study adds.
Lorelei Lingard discusses a similar distinction in the problem, gap, and hook approach. The problem identifies an issue. The gap explains what remains unknown regarding that issue. The reason for addressing the gap explains why the reader should care about the answer.
The same sleep study can contain each part:
| Part | What it tells the reader | Sleep and exams example |
|---|---|---|
| Topic | What was studied | Sleep and exam scores among first-year students |
| Problem | Why the topic matters | Students who sleep less often receive lower scores, but advice often focuses on the night before an exam |
| Research gap | What previous studies have not established | Earlier studies measured sleep on the night before an exam. They have not established whether the association remains when they measure sleep across the week. |
| Why the gap matters | Why answering the question is useful | If sleep across the week matters, advice focused on one night may overlook an important part of the problem |
| Contribution | What the new study adds | The association remains when sleep is measured across the week, suggesting that the pattern is not limited to the night before the exam |
Many papers can share the same topic. The research gap needs to explain what remains unanswered in the specific body of research that leads to your study.
Where does the research gap appear in a paper?
The research gap usually appears in the introduction. It may also appear in a shorter form in the abstract.
In the abstract, the gap helps explain why the study was needed. Nature’s guidance for summary paragraphs asks authors to move from the research context to the unresolved issue and then to the major result.
Our guide on how to write a research paper abstract explains how the background, gap, method, and result fit together.
The introduction gives the author more space to develop the gap. Swales’s CARS model for research introductions describes a common sequence:
- Explain the research area.
- Identify what remains unresolved.
- Explain how the current study addresses it.
We discuss this structure in more detail in our guide on how to structure a research paper introduction.
A gap can come from a missing measurement, conflicting findings, an untested population, or a limitation in previous methods. Some papers develop this discussion in the literature review and then state the major gap again near the end of the introduction.
Those statements need to agree. If the literature review says that weekly sleep is the missing evidence but the introduction later presents caffeine use as the major problem, the purpose of the study becomes unclear.
The gap also needs to appear before the purpose of the study. Readers first need to understand what is unknown before they can understand why the new study is needed.
An unclear or missing gap can make the motivation for the study difficult to follow. Our guide on common reasons for desk rejection discusses this problem in more detail.
How do you identify a research gap?
A research gap arises from reading the studies closest to your research question and comparing what they found, measured, and left unresolved.
Nyanchoka and colleagues found that systematic and scoping reviews are common ways to identify research gaps in health research. For a single empirical paper, the same principle can be applied on a smaller scale by carefully comparing the studies most relevant to your question.
Christoph Müller-Bloch and Johann Kranz argue that research gap identification needs a clear and repeatable process. Another researcher reading the same body of work should be able to understand why you identified the gap.
A simple process is:
- Record the population, measure, main finding, and limitation of each closely related study.
- Compare the studies and look for a pattern. They may use the same measure, exclude the same population, or report conflicting results.
- Write what the studies have established and what they have not established.
A useful draft is:
Previous studies have established ____. They have not established ____ because ____.
The reason matters.
Compare:
Few studies measured weekly sleep.
This tells us that there are few papers.
Now compare:
Previous studies measured sleep on a single night, so it remains unclear whether the association with exam scores reflects one night of sleep or a longer pattern.
The second statement identifies the question that the missing evidence leaves unanswered.
Before using the gap in your paper, search again for studies that may already have answered the question. Our guide on checking citations and supporting claims explains how to review the literature before making a novelty claim.
How do you write a research gap statement?
Karen Locke and Karen Golden-Biddle found a common structure when they examined how published studies establish research contributions. Authors explain what earlier research has established, identify what remains unresolved, and then state how the current study addresses the issue.
Applied to the sleep study, the gap could be written as:
Previous studies have linked short sleep on the night before an exam with lower scores. However, these studies measured sleep during a single night. They have not established whether the same association appears when sleep is measured across a full week. It therefore remains unclear whether the relevant period is the night before the exam or a longer pattern of sleep.
The purpose can then follow:
This study measures sleep across seven days in first-year students and tests whether the association between sleep and exam scores remains.
The relationship between the two statements is direct. The gap asks whether the association remains across a week. The study measures a week of sleep and tests that association.
Wayne Booth, Gregory Colomb, and Joseph Williams provide another way to develop the idea in The Craft of Research:
- I am studying ____.
- because I want to find out ____.
- to help my reader understand ____.
The second line can help identify the unanswered question. Once you have reviewed the closest studies, rewrite that question as a statement about what previous research has not established.
The third line explains why answering the question matters.
Brett Mensh and Konrad Kording make a related point in Ten simple rules for structuring papers. A paper needs a clear central message. If readers understand the topic but cannot identify what was unknown before the study, the research gap is not clear enough.
What kinds of research gaps can you write?
Research gaps can arise from distinct problems in the existing evidence. The gap needs to match the question your study actually examines.
Missing evidence
Previous studies may not contain enough evidence to answer a specific question.
Suppose earlier research measured sleep on the night before an exam, while a new study measures sleep across seven days. The missing evidence is not simply the absence of a seven-day dataset. The important question is whether measuring a longer period changes what researchers can conclude.
A clear gap would be:
Previous studies have not established whether the association between sleep and exam scores remains when sleep is measured across a full week.
By comparison:
We will collect seven days of sleep data.
This describes the method, not the research gap.
Conflicting evidence
A research gap can exist when previous studies report different results.
One study may find that short sleep is associated with lower exam scores, while another finds no association. The gap is not simply that the findings are mixed. The useful question is whether there is a reason for the difference.
For instance, studies that find an association may measure sleep on the night before the exam, while studies that do not find one may measure sleep across a typical week.
The gap could then be:
It remains unclear whether differences in the sleep measurement period explain the conflicting results reported in previous studies.
This gives the new study a question it can test.
An untested population or setting
Another population or setting may not have been tested with an established finding.
Suppose previous studies reported an association between sleep and performance among working adults. A new study may examine first-year university students, whose schedules and living conditions differ from those of the earlier participants.
The gap needs to remain limited to what the literature supports. A study at one university cannot claim that the relationship has never been examined in any student population unless the literature review supports that statement.
A method that cannot answer the question
A research gap can also arise from a limitation in the methods used by earlier studies.
A single question about sleep on the previous night cannot show whether an observed association reflects one night or a longer sleep pattern. A seven-day diary or another measure covering several days may allow the researcher to examine that question.
The gap is not the absence of a specific method. It is the unanswered question caused by the limits of the earlier methods.
Using a different method becomes important when it allows the study to answer something that previous methods could not.
What makes a research gap statement weak?
A research gap becomes weak when it names a broad topic, relies only on novelty, does not match the study design, or disappears after a more complete literature search.
It names the field instead of the unknown
Little is known about sleep and learning.
This sentence identifies a broad research area but does not explain what previous studies have already established or what remains unresolved.
A stronger statement identifies a specific unanswered question.
It treats being first as the gap
This is the first study of weekly sleep and exam scores in first-year students at this university.
The statement may be correct, but being first does not explain what the study helps researchers understand.
The reader still needs to know what was missing from previous research and why the new study addresses that problem.
The gap does not match the study
Suppose the introduction says that the effect of weekly sleep remains unknown, but the study measures sleep only on the night before the exam.
The design cannot answer the question stated in the gap.
Check each important part of the gap against the methods. If the gap concerns a population, measure, comparison, or explanation, the study needs data or analysis that can address it.
The literature search is incomplete
A gap may appear to exist because an important paper was missed.
If one relevant study already answers the question, the original gap statement may no longer be valid. Researchers who know the field may notice the missing study immediately.
Search the literature again before making statements such as “no studies have examined” or “this question remains unanswered.”
Jörgen Sandberg and Mats Alvesson found that identifying gaps is a common way to develop research questions. Alvesson and Sandberg later argued in Generating research questions through problematization that simply finding an unstudied combination of variables can lead to a weak contribution.
For example:
Nobody has studied X and Y together.
This tells us that a particular combination may be new.
A stronger gap explains why the missing knowledge matters:
Without testing X and Y together, previous studies cannot determine whether X changes the relationship between Y and Z.
The second statement gives the study a simple question to answer.
How do you check your research gap before submitting?
Start with the abstract and introduction. Without reading the methods, complete this sentence:
Previous research has not established ____.
Your answer should identify a specific unknown.
If the blank contains only the research topic, the gap is too broad. If it contains the result you expect to find, you are describing a contribution rather than the unanswered question.
The abstract and introduction should lead to the same answer.
Next, read the methods and ask whether the study can address that unknown. A gap about weekly sleep needs a measure that covers the week. A gap about conflicting findings needs a design or analysis that can examine why those findings differ.
Then ask someone who has not read the paper to read the introduction and answer two questions:
- What is still unknown?
- Why does that unknown matter?
If their answers differ from what you intended, the gap may need to be stated more clearly.
Academic review tools such as Fukurō can help check whether a gap is stated and whether the major claims remain consistent across sections. They cannot establish whether the gap truly exists in the published literature. That still requires a careful literature search.
Before submitting, ask one last question:
Can a reader identify what previous research has not answered, why the answer matters, and how this study addresses that question?
If all three parts are clear and supported by the paper, the research gap is well-defined.
References and useful policies
- Nyanchoka L, Tudur-Smith C, Thu VN, et al. A scoping review describes methods used to identify, prioritize and display gaps in health research. Journal of Clinical Epidemiology. 2019;109:99-110.
- Grant AM, Pollock TG. Publishing in AMJ, part 3: setting the hook. Academy of Management Journal. 2011;54(5):873-879.
- Swales JM. Genre Analysis: English in Academic and Research Settings. Cambridge University Press; 1990. See also the UMass Amherst Writing Center CARS guide.
- Nature. How to construct a Nature summary paragraph.
- Robinson KA, Saldanha IJ, McKoy NA. Development of a framework to identify research gaps from systematic reviews. Journal of Clinical Epidemiology. 2011;64(12):1325-1330.
- Lingard L. Joining a conversation: the problem/gap/hook heuristic. Perspectives on Medical Education. 2015;4(5):252-253.
- Müller-Bloch C, Kranz J. A framework for rigorously identifying research gaps in qualitative literature reviews. ICIS 2015 Proceedings. 2015.
- Locke K, Golden-Biddle K. Constructing opportunities for contribution: structuring intertextual coherence and “problematizing” in organizational studies. Academy of Management Journal. 1997;40(5):1023-1062.
- Booth WC, Colomb GG, Williams JM, et al. The Craft of Research. 5th ed. Chicago: University of Chicago Press; 2024.
- Mensh B, Kording K. Ten simple rules for structuring papers. PLoS Computational Biology. 2017;13(9):e1005619.
- Sandberg J, Alvesson M. Ways of constructing research questions: gap-spotting or problematization?. Organization. 2011;18(1):23-44.
- Alvesson M, Sandberg J. Generating research questions through problematization. Academy of Management Review. 2011;36(2):247-271.