An examiner asks, “What research gap does your study fill?” and you answer, “There are few studies on this topic.” Why is that not convincing? Because a shortage of studies describes the literature, not a shortfall in knowledge; a topic may be under-researched simply because it does not deserve attention. A research gap is a specific, nameable deficit: you can say what kind of thing is missing (evidence, a method, a population, a theory) and show it in a table of studies. This guide separates gaps from non-gaps, explains the seven gap types, offers four ways to find one, shows how to prove it with an evidence table, and gives the wording for a master’s or PhD proposal.
This article is part of our guide How to Write a Master’s Thesis by the Mastermind PhD team and relates to our Literature Review support service. Sources last checked: November 2026.
What is a research gap? A research gap is a question that the existing literature has not answered adequately: because nobody has studied it, because it was studied with a method, sample or setting that does not transfer to your case, because the findings conflict, or because theory or practice has moved beyond the evidence. A gap is named by its type and demonstrated by systematic comparison across studies; it becomes a research problem when you can also show, with evidence from the field, that closing it matters.
What does not count as a research gap?
- Few or no studies on a topic, with no argument for why the topic needs studying.
- “It has not been studied in my country” without a reason to expect the findings to differ from the settings already studied.
- Replication with a new sample from the same population and no added variable, method or comparison.
- A broad, important topic (“artificial intelligence in education”) with no specific unanswered question.
- A gap in your own reading. Something you have not read is not something the field does not know; this is the gap examiners detect fastest.
What are the seven types of research gap?
Miles (2017) synthesized earlier work into a taxonomy of seven gap types. Naming the type tells the examiner exactly what is missing and dictates what kind of study can fill it.
| Gap type | What is missing | Example | Study that fills it |
|---|---|---|---|
| Evidence gap | Findings from different studies contradict one another or are inconclusive | Some studies find a positive link between teaching experience and burnout, others a negative one | A study designed to resolve the contradiction, often by testing a moderator |
| Knowledge gap | The question has not been studied, or exists only as a proposed model | A model of organizational trust has been published but never measured | A first empirical test of the model |
| Practical-knowledge gap | Professional practice differs from what research recommends, and the difference itself is unstudied | Schools run leadership programs not based on any evaluated model | A study that documents and explains the divergence |
| Methodological gap | All existing studies share one method, which limits what can be concluded | Only cross-sectional questionnaire studies; no longitudinal or mixed-methods work | A study using the missing design |
| Empirical gap | A theoretical proposition has not been evaluated empirically, or has been tested only once | A theory supported by a single study in one country | A replication or extension with a new sample |
| Theoretical gap | Competing theories have not been compared, or no theory connects the variables | No framework links leadership, trust and commitment in one model | A study that tests or integrates the competing accounts |
| Population gap | A group with characteristics that justify separate study has not been studied | Vocational-school teachers versus general-education teachers, with a reason the results should differ | A study of the under-represented group, with the difference justified |
Most master’s theses fill a knowledge, population or evidence gap. Methodological and theoretical gaps are more common at doctoral level, because the study that fills them must be designed differently from everything that came before.
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How do you find a gap? Four methods that produce evidence as you go
- Build a literature matrix. One row per study (25 to 40 for a master’s thesis, more for a PhD) and columns for variables, theory, design, sample, setting, main finding and the authors’ stated limitations. Empty cells and uniform columns are gaps: an empty “mediator” column, or a “design” column that reads “cross-sectional survey” forty times. Webster and Watson (2002) describe this concept-centric approach; it is the strongest method because the matrix is also your proof.
- Mine the limitations and future-research sections. Every peer-reviewed article states what it did not do. Collect these statements from ten recent studies and you have gaps declared by the people who know the literature best, each with a citation attached.
- Look for contradictions. When studies disagree, ask what differs between them: sample, measurement, context, or an unmeasured third variable. Explaining a contradiction is an evidence gap and often a theoretical gap as well.
- Extend a theory to a new context, with a reason. A model that works in banking may not hold in public hospitals. The gap is contextual, and it is legitimate only if you can name the features of the new context (incentives, regulation, professional culture) that make the transfer uncertain.
How do you prove the gap with an evidence table?
The evidence table is a condensed version of the matrix that appears in the proposal or its appendix. Its last row states the gap as an unfilled cell.
| Study | Variables | Design and sample | Setting | Finding | What it did not do |
|---|---|---|---|---|---|
| Hospital survey (2021) | Transformational leadership, commitment | Questionnaire, 300 nurses | Public hospitals | Moderate positive association | No mediator; health sector only |
| Banking survey (2022) | Leadership, commitment, satisfaction | Questionnaire, 250 employees | Commercial banks | Satisfaction partially mediates | Banking only |
| School survey (2023) | Commitment, demographics | Questionnaire, 400 teachers | Secondary schools | Commitment moderate; varies by experience | No leadership variable |
| Interview study (2024) | Leadership, trust | Interviews, 15 principals | Secondary schools | Trust proposed as the mechanism | Qualitative; not tested quantitatively |
| The gap | Trust as mediator between leadership and commitment | Quantitative, adequately powered | Public secondary schools | Not yet examined | Not yet examined |
Read down the last column and the gap writes itself: trust as a mediator has been proposed qualitatively and tested only outside education. The table replaces a paragraph of assertions with something an examiner can check line by line.
Worked example: from 32 studies to one gap sentence
A student in a faculty of education wants to study teachers’ organizational commitment. Her four steps:
- She enters 32 studies published between 2018 and 2026 into a matrix with the columns above.
- The “mediator” column is empty for every education study, while two health-sector studies tested trust and one banking study tested satisfaction.
- The future-research sections of three recent articles explicitly recommend testing the mechanisms of the leadership-commitment link in schools.
- A search of two thesis repositories and Google Scholar for the three variables together, restricted to the last two years, finds no quantitative test in schools.
The gap is two things at once: a knowledge gap (an untested mechanism) and a justified population gap (schools differ from hospitals and banks in authority structure and incentives). The gap sentence reads: “Although studies agree that transformational leadership is associated with organizational commitment, the mechanism of this association through organizational trust has not been tested quantitatively in secondary schools, where the structure of authority and incentives differs from the sectors studied so far.” The table goes in the appendix, the sentence in the problem statement, and the three recommending articles are cited in the literature review.
Repeat step 4 just before submission, with Google Scholar alerts running on your key terms in the meantime: a gap found in March can be filled by July, and a close new study is better added to the matrix now than discovered at the defense.
How do you phrase the gap in the proposal?
The gap appears in three places, each with a different job.
In the problem statement, one or two sentences that move from what is known to what is not: “Previous studies have examined the relationship between transformational leadership and commitment in health care and banking (citations). A qualitative study (citation) proposed organizational trust as the mechanism of this relationship, but the mechanism has not been tested quantitatively in secondary schools, where authority and incentive structures differ from the sectors studied.”
In the literature review synthesis, a paragraph with four moves: what the studies agree on; where they disagree; the type of gap and the evidence for it (refer to the table); and how the present study fills it (variable, design, population), including what it borrows from earlier work, such as an instrument or a model.
In the significance section, one sentence linking the gap to the contribution: “By testing trust as a mediator in schools, the study extends the model from commercial to educational settings and tells school leaders which mechanism to target.”
Use the type label explicitly. “This study addresses a methodological gap” tells the examiner what to expect; “little is known” tells them nothing.
Which mistakes make examiners doubt the gap?
- A gap asserted in a sentence but never shown in a table.
- A gap type that does not match the design: a methodological gap (only surveys exist) “filled” with another survey.
- An existing thesis on the same variables and population that the student did not find; examiners in the field usually know it.
- A contextual gap with no argument for why the context should change the results, or a gap so wide that it needs a research program rather than a thesis.
- Confusing the gap (in the literature) with the problem (in the field); the problem statement needs both.
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Frequently asked questions
How many studies do I need to demonstrate a gap in a master’s thesis?
A matrix of 25 to 40 recent, relevant studies is usually enough, provided it includes the foundational works, the main peer-reviewed studies of the last five to seven years, and theses from the repositories your examiners know. Depth of comparison matters more than the raw count.
I found a study that fills my gap exactly. What now?
Read it in full, including its limitations and future-research sections, then reposition your gap to build on it: a different mediator, a longitudinal or mixed design, a justified new population, or a replication that tests whether the finding holds. Present the study openly as the closest prior work; omitting it is a professional error that is easily discovered.
Is a contextual (population) gap enough for a master’s thesis?
It can be, if you justify it with features of the context that make the transfer of earlier findings uncertain, and if you strengthen it with a small addition such as a meaningful comparison, an adapted instrument or an added variable. At doctoral level a contextual gap alone is rarely sufficient.
What is the difference between a research gap and a research problem?
The gap is a shortfall in the literature; the problem is a discrepancy between what happens in the field and what should happen. A proposal needs both: the problem shows the question matters in practice, and the gap shows you are not repeating work that has already answered it.
Can AI tools identify a research gap?
They can summarize articles you have read, organize the matrix and draft alternative wordings. They do not know the specific literature of your subfield or unindexed theses, and they sometimes produce references that do not exist. The gap must come from your own reading and your own matrix, and every citation in it must be one you have opened.
Sources
- Miles, D. A. (2017). A taxonomy of research gaps: Identifying and defining the seven research gaps. Paper presented at the Doctoral Student Workshop: Finding Research Gaps, Journal of Research Methods and Strategies.
- Robinson, K. A., Saldanha, I. J., & McKoy, N. A. (2011). Development of a framework to identify research gaps from systematic reviews. Journal of Clinical Epidemiology, 64(12), 1325–1330. https://doi.org/10.1016/j.jclinepi.2011.06.009
- Müller-Bloch, C., & Kranz, J. (2015). A framework for rigorously identifying research gaps in qualitative literature reviews. Proceedings of the 36th International Conference on Information Systems (ICIS), Fort Worth, Texas.
- Webster, J., & Watson, R. T. (2002). Analyzing the past to prepare for the future: Writing a literature review. MIS Quarterly, 26(2), xiii–xxiii.
- Hart, C. (2018). Doing a Literature Review: Releasing the Research Imagination (2nd ed.). SAGE.
- Booth, W. C., Colomb, G. G., Williams, J. M., Bizup, J., & FitzGerald, W. T. (2016). The Craft of Research (4th ed.). University of Chicago Press.
Sources last checked: November 2026. This article is general educational guidance and does not replace your university regulations or your supervisor’s instructions. How we prepare our content.