If you’re starting a PhD or progressing through your first year, you’ve likely heard the phrase “research gap” countless times. Whether you’re preparing your literature review chapter or developing your proposal, identifying a clear research gap is essential for justifying your study. But what does this term actually mean, and more importantly, how do you find one?
In this post, we’ll explore the meaning of research gaps, the types of research gaps you might encounter, and practical strategies for identifying research gaps within your field. By the end, you’ll have a clearer understanding of how to find research gaps and how to approach the literature review with a critical and strategic mindset.
What Are Research Gaps?
Let’s start with the basics: research gaps refer to the areas within existing academic literature that are either underexplored, unexplored, contradictory, or outdated. In other words, a research gap is an opportunity to contribute something new to your field.
Finding a research gap is about more than just spotting an empty space. It’s about identifying where your work can add value—whether that’s by offering a new perspective, using a different method, or applying theory to a new context.
In a PhD, your ability to locate and clearly articulate a research gap is critical. It underpins your entire project: without a justified gap, your research risks being seen as redundant or unfocused.
Why Is Identifying Research Gaps So Important in a PhD?
A PhD is a contribution to knowledge. That contribution only becomes clear if you can demonstrate that existing research doesn’t fully answer your research question, or that the field hasn’t yet asked that question yet.
Your literature review isn’t just a summary of what’s been published. It’s a critical analysis that leads your reader toward your research gap. You need to show that:
- You understand the key debates in your field
- You’re aware of the work that has already been done
- You’ve identified a space where further investigation is needed
In other words, identifying research gaps helps build your authority and justifies your PhD project.
Types of Research Gaps
There are several types of research gaps that PhD students may come across during their literature review. Understanding these categories can help you spot opportunities for your own research.
1. Theoretical Gaps
These occur when a concept or theory hasn’t been fully explored or applied in a particular context. For instance, if most studies use one theoretical model, but an alternative framework might offer new insights, that could be your gap.
2. Methodological Gaps
These arise when a specific method hasn’t been used to study a topic, or when previous methods have limitations. You might find that existing studies rely too heavily on qualitative methods, for example, and a quantitative approach could offer a fresh perspective.
3. Empirical Gaps
This refers to gaps in the actual data—perhaps a particular population, region, or time period hasn’t been studied. If research is focused on Western countries, but little is known about how the same phenomenon appears in the Global South, there may be an empirical gap.
4. Population Gaps
Similar to empirical gaps, population gaps refer to the lack of research on certain groups, such as marginalised communities, non-binary individuals, or people with disabilities.
5. Practical or Policy Gaps
These gaps relate to real-world applications. Maybe research has been done on a theoretical level, but there’s little work examining how those ideas work in practice, or how they inform policy decisions.
6. Contradictory Findings
Sometimes the gap lies in unresolved debates. If two or more studies offer conflicting results or interpretations, you could step in to resolve or reframe the discussion.
How to Identify Research Gaps
Now that we’ve defined research gaps and explored their types, let’s move to the practical side of things: how to identify research gaps in the literature.
1. Read Systematically and Critically
It’s tempting to dive into articles and start summarising, but effective literature reviews require more than reading for content. Instead, read with questions in mind:
- What questions is this research trying to answer?
- What assumptions does it make?
- What are the limitations of the study?
- What does the author say about future research?
Take notes on these areas as you go. Look especially at the “Limitations” and “Further Research” sections at the end of academic papers—these often point directly to possible gaps.
2. Look for Patterns and Themes
As you review more literature, you’ll start to notice patterns. What topics are heavily researched? Which methods are used most often? What’s missing?
Create thematic maps or tables to categorise studies by topic, method, theory, or population. This will help you visualise the state of research in your area and spot any imbalances.
3. Use Review Articles and Meta-Analyses
Systematic reviews and meta-analyses provide a broad overview of existing literature. They’re incredibly useful for identifying research gaps, as they often highlight underexplored areas and limitations in existing research.
Search for these reviews in your area and pay attention to their recommendations for future research.
4. Consult Your Supervisor and Peers
Sometimes we miss the obvious. Talking through your findings and ideas with your supervisor or research group can help reveal blind spots or confirm the value of a potential gap. They may also point you towards relevant work you haven’t yet encountered.
5. Follow Citation Trails
If you find a useful article, check who they’ve cited—and who has cited them since. This allows you to trace how conversations have evolved and helps you spot where discussions have stalled or shifted.
6. Use Research Databases Intelligently
Make use of advanced search options in databases like Scopus, Web of Science, or your university library portal. Use combinations of keywords, limit by date or location, and experiment with different terms to widen or narrow your search.
Keep refining your searches as your focus becomes clearer. The goal is not to read everything, but to read strategically and effectively.
Common Challenges in Finding Research Gaps
Many PhD students struggle with the process of how to find research gaps, especially in broad or interdisciplinary fields. Common obstacles include:
- Feeling overwhelmed by the volume of existing research
- Worrying that “everything has already been done”
- Finding too many small gaps and not knowing which to pursue
- Identifying a gap that is too broad or too narrow
The key is to remember that your gap doesn’t need to revolutionise the field. It just needs to be credible, original, and researchable. Focus on where your interests, skills, and the needs of the field align.
How Research Gaps Shape Your Literature Review
Your literature review isn’t just a background chapter—it’s where you build the case for your study. Everything in the review should lead your reader to one conclusion: that there is a compelling research gap, and your PhD will fill it.
To do this well:
- Structure your review thematically or methodologically
- Critically engage with the literature, not just describe it
- Show how your work builds on, diverges from, or addresses limitations in past research
- End with a clear articulation of your research gap and how your study addresses it
Finding Your Space in the Academic Discourse
Discovering and articulating a research gap is a defining moment in any PhD. It’s what transforms you from a reader of research to a contributor. The process may feel overwhelming at first, but by approaching the literature critically, systematically, and strategically, you can identify where your voice is needed most.
Remember: research gaps aren’t always obvious. They’re often subtle, complex, or interdisciplinary. But they are there, and your job as a researcher is to locate them, understand them, and respond to them through your study.
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