How to Write the Literature Review Chapter of a PhD Thesis Proposal (A Beginner’s Guide)

The second chapter of a PhD thesis proposal in most cases is the literature review. The literature review chapter is where most PhD thesis proposals quietly fall apart. Not because students don’t read enough, but because they don’t know what to do with what they’ve read.

This guide walks you through the full process: from finding literature to organising it, from building a theoretical review to drawing your conceptual framework, and from identifying research gaps to avoiding the mistakes that get proposals sent back.

What Is the Literature Review Chapter For?

The second chapter of a PhD thesis proposal is, in most institutions, the literature review. Its job is to show your committee three things:

• that you understand the theories relevant to your topic,
• that you know what has already been studied empirically, and
• that you can identify exactly what still needs to be studied — which becomes the justification for your research.

Done well, Chapter 2 does more than summarise other people’s work. It builds the case for your study. Everything you write in Chapter 1 about the “gap in knowledge” has to be backed up here, with evidence.

Before You Write: How to Search and Organise Literature

Most guides skip straight to “review the theories” without addressing the part students actually get stuck on first: finding and managing the literature itself.

Where to search:

• Google Scholar (free, broad coverage — start here)
• Your university library’s subscription databases (JSTOR, ScienceDirect, EBSCOhost, ProQuest)
• Subject-specific databases (PubMed for health sciences, IEEE Xplore for engineering, EconLit for economics)
• Grey literature sources (government reports, NGO publications, working papers) when your topic needs current, real-world data that hasn’t been published in peer-reviewed journals yet

Also read:

Where to Find Journal Articles for PhD Research (7 Best Sources)

How to search effectively:

• Use Boolean operators: “maternal health” AND “postpartum” AND Kenya
• Search using your key variables, not your whole topic sentence
• Check the reference lists of 2–3 recent, highly-cited papers in your area — this “snowballing” technique often surfaces sources faster than a fresh search
• Set a cut-off: aim for the most recent 5–10 years of literature, with a few older foundational or seminal works included for theory

Also read:

Boolean Operators and Modifiers: Effective Search Strategies for PhD Students

Tools to manage what you find:

Use a reference manager from day one — retrofitting citations later is one of the most time-consuming mistakes PhD students make. Zotero and Mendeley are free and both integrate with Word for automatic in-text citations and reference lists. Rayyan is useful if your review involves screening a large number of abstracts and is most suitable for systematic and scoping reviews.

Also read:

How To Use Zotero For Reference Management (An Illustrative Guide)

How To Use Mendeley For Reference Management (An Illustrative Guide)

Introduction to the Chapter

This section is usually just a paragraph long. It tells the reader what the chapter will cover and, briefly, how it is organised — for example, whether you’ll move from theoretical review to empirical review to conceptual framework, in that order.

Theoretical Review

The theoretical review follows the chapter introduction. Here, you review the theories behind the topic under investigation. For each relevant theory, cover:

• Who developed the theory, and when
• The theory’s main arguments or propositions
• How the theory has previously been applied to study your problem, or similar problems

Most topics are explained by more than one theory. Review all the theories that are relevant, then do a short comparative analysis — how do they differ, where do they overlap, which one has the most explanatory power for your specific problem? End the section by naming the theory (or theories) that will underpin your study, with a clear justification for that choice. This becomes your theoretical framework, and examiners will ask you to defend it, so don’t skip the justification.

Empirical Review

After the theoretical review, you review empirical studies related to your problem. Empirical literature refers to original studies — ones based on actual data collection and analysis — as opposed to purely theoretical papers.

This is the section that separates a strong literature review from a weak one, because it requires critique, not summary. Avoid writing sentence after sentence of “Author A (2022) found X. Author B (2023) found Y.” Instead, engage with the studies:

• What did each study find, and how strong is the evidence?
• Where do studies agree? Where do they contradict each other — and why?
• If two studies on the same topic reach different conclusions, examine why: different populations, different methodologies, different contexts, different sample sizes?
• What are the limitations of the existing studies, and how does that create room for your research?

A useful habit: after reading each source, write one sentence answering “So what does this mean for my study?” before moving to the next one. That sentence is often the seed of your critique.

Chronological vs. Thematic Organisation of Empirical Literature

There are two common ways to organise your empirical review.

Chronological Organisation

Literature is organised by date of publication, oldest to most recent.

Advantage: shows how understanding of the problem has evolved over time.

Disadvantage: the discussion can feel disjointed, since similar studies get separated simply because they were published years apart.

Thematic Organisation

Literature is grouped by theme or variable rather than by date. Each variable in your study gets its own subsection, where all the studies that examined it are discussed together — highlighting where they agree and where they disagree.

Advantage: creates a smoother, more analytical flow, and makes it much easier to spot research gaps within each theme.

While the choice varies by institution, thematic organisation is generally preferred at PhD level, because it demonstrates synthesis rather than just a summary of individual papers.

Using a Literature Synthesis Matrix

Before you start writing full paragraphs, build a simple synthesis matrix — a table with one row per study and columns for: author/year, purpose, theory used, methodology, key findings, and limitations.

This does two things:

• First, it forces you to extract the information you actually need rather than re-reading full papers when you sit down to write.
• Second, once the matrix is filled in, patterns jump out visually — you can literally see where studies cluster (a well-covered theme) and where rows are thin or contradictory (a potential gap).

Many students find this single step cuts their writing time in half, because the analytical work happens before the writing, not during it.

Not sure how to create the literature synthesis matrix? Download our free ready-to-use literature synthesis matrix and get started with your literature review.

Developing a Conceptual Framework

Once the theoretical and empirical reviews are complete, the next step is to develop your own conceptual framework — a diagrammatic representation of the variables in your study and the relationships between them. This is especially important for quantitative studies.

Building the conceptual framework involves three steps:

1. Identifying all the variables that will be analysed in your study (independent, dependent, and any moderating or mediating variables).
2. Specifying the relationships between those variables, based on what the literature review revealed.
3. Drawing the diagram — typically boxes for variables, ovals for constructs, and arrows showing the direction of the hypothesised relationships.

A simple example: if your study examines how access to prenatal care (independent variable) affects postpartum depression rates (dependent variable), with social support as a moderating variable, your diagram would show an arrow from access to prenatal care to postpartum depression, with social support positioned to show its moderating effect on that relationship. Keep the diagram as simple as the relationships require — resist the urge to add variables just because a paper mentioned them if they are not central to your study.

Identifying Research Gaps

The core purpose of the literature review is to document what is known — and what is not. Research gaps are the “not yet known” part, and your contribution to knowledge comes from addressing one of them.

This is why the literature review should genuinely come before you finalise your topic, not after: reviewing existing work first, then settling on your specific angle, produces a much stronger justification than picking a topic and searching for gaps to fit it retroactively.

There are three broad types of research gaps:

• Conceptual gaps — a variable or angle that hasn’t been studied. Example: most maternal health studies focus on pregnancy and delivery, but not the postpartum period.
• Scope gaps — differences in coverage:
  • Geographical: rural vs. urban, or one country/region vs. another
  • Time: older studies vs. current conditions
  • Demographic: different age groups, income levels, or genders
• Methodological gaps — differences in how the topic has been studied:
  • Design: quantitative vs. qualitative vs. mixed methods
  • Data collection: surveys vs. interviews and focus group discussions
  • Analysis technique: descriptive vs. inferential statistics

Naming the specific type of gap your study addresses — rather than vaguely stating “a gap exists” — is one of the fastest ways to strengthen your justification in the eyes of an examiner.

Download our research gap finder worksheet that will help you identify your own research gap.

How Long Should the Literature Review Chapter Be?

There’s no universal rule, since requirements vary by institution and discipline, but as a general guide, Chapter 2 is typically the longest chapter in a proposal — often 30–45% of the total proposal length. What matters far more than page count is density: a shorter, tightly synthesised review that clearly builds toward your research gap will always outscore a longer one that reads like a list of summaries. Check your own department’s handbook for any specific page or word requirements before finalising.

Chapter Summary

Close the chapter with a short section summarising what it covered and restating, in a sentence or two, the main research gap your study will address. This sets up a natural bridge into Chapter 3, where you explain your methodology for addressing that gap.

Common Mistakes to Avoid in the Literature Review Chapter

• Summarising instead of synthesising. Restating what each study found, one after another, without comparing or critiquing them.
• No visible link to Chapter 1. The gap you identify here must be the same gap referenced in your problem statement — examiners check for this consistency.
• Outdated sources. Relying heavily on literature that is more than 10 years old, with no recent studies to show the field has moved.
• A conceptual framework with no basis in the review. Every variable and relationship in your diagram should be traceable back to something discussed earlier in the chapter.
• Vague gap statements. “Few studies have been done on this” is not a research gap — it needs to specify what kind of gap, and why it matters.
• Weak citation management. Missing in-text citations, inconsistent reference formatting, or reference list entries that don’t match in-text citations. This is one of the easiest things to fix — and one of the most common reasons proposals get sent back for what feels like a “small” reason.

Final Thoughts

Chapter 2 is often the most daunting part of a PhD thesis proposal — partly because it’s substantial, and partly because it directly informs Chapter 1. Writing a strong “contribution to knowledge” section in Chapter 1, for instance, is only possible once you have genuinely read and synthesised the literature in Chapter 2. Formats vary between institutions, so always check your department’s specific guidelines — but the underlying logic (theory → evidence → gap → your study) holds across almost all of them.

Frequently Asked Questions

Is the literature review always Chapter 2? In the standard 3-chapter proposal structure (Introduction, Literature Review, Methodology), yes. Some institutions use a 5-chapter full-thesis structure instead, where the literature review may appear later, but the content and logic described here still apply.

Should I include a conceptual framework if my study is qualitative? It’s less common, but many qualitative studies still benefit from a simpler conceptual or thematic framework showing how key concepts relate. Confirm with your supervisor what’s expected in your discipline.

How many sources should Chapter 2 include? There’s no fixed number — it depends on how established your field is. What matters is that your review is current, relevant, and sufficiently comprehensive that an examiner can see you know the field, not that it hits a specific citation count.

What’s the difference between a theoretical framework and a conceptual framework? A theoretical framework is the established theory (or theories) you’re applying to your problem. A conceptual framework is your own diagram of the specific variables and relationships in your study, informed by that theory and the empirical literature.

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