In health sciences dissertations, the literature review usually spans about 20–40% of the total word count, set by your program.
When you ask how long the literature review should be, you’re really asking how much space you need to map the field, show the debate, and justify your study. In health sciences, that space changes with degree level, project scope, and whether your review is narrative, scoping, or systematic. Plan a range, then tune it with your supervisor and your handbook after a draft.
How Long Is The Literature Review In A Health Sciences Dissertation: Practical Range
Across health programs, a steady rule of thumb works: set the literature review at about one fifth to two fifths of the full thesis. Masters projects with a 10,000–20,000 word limit often land near the lower end. Doctoral projects with 40,000–80,000 words trend higher, especially when the review anchors a complex method or a publishable papers format. Your local rules always win, so treat the table below as a planning guide, not a fixed quota.
| Degree | Total Thesis Words | Lit Review Range |
|---|---|---|
| Masters (Health) | 10,000–20,000 | about 2,000–6,000 (20–30%) |
| Professional Doctorate | 30,000–50,000 | about 6,000–15,000 (20–35%) |
| PhD (Health Sciences) | 40,000–80,000 | about 8,000–20,000 (20–30%+) |
Why The Range Works
Health work spans practice, data, and policy, which widens the evidence base. A tight bench study may need less background than a project that threads trials, cohorts, and implementation work. Systematic review chapters add method text and run longer. A manuscript style thesis may compress Chapter 1 and push topic framing into each paper.
Program Rules You Must Check
Every school sets thesis word limits or page ranges. Those limits decide your ceiling. Health faculties often post ranges for MPhil, MD, or PhD submissions; plan inside those bands and size your review in line with your total allowance. See the University of Sheffield’s word limits for health faculties for a clear example of how totals are set. For the shape and purpose of the chapter, follow your program’s writing guide and the expectations set by your committee.
What Drives The Word Count
Review Type
Narrative reviews synthesize major themes and debates. They tend to sit near the low end of the range because methods are brief and the goal is a critical map, not a full audit of studies. Systematic or scoping reviews include protocol choices, search strings, screening flow, and risk of bias notes. That extra method text pushes length upward and often justifies a larger share of the thesis.
Degree Level And Contribution
Masters work needs to show command of the field and a clear gap. Doctoral work also positions a novel contribution. That second aim usually needs a deeper build-up, which drives a longer review. If your thesis uses a publishable papers route, your introduction chapter must knit the articles together; budget more words there.
Topic Breadth And Evidence Mix
A narrow lab topic with tight prior art needs less space than multi-site public health research that spans trials, qualitative work, and surveillance data. If your topic cuts across species or settings, your map widens and the chapter grows.
Supervisor And Committee Preferences
Committees differ on how much background they want in Chapter 2 versus the discussion. Some prefer a lean, incisive review; others want a deep context chapter. Ask early. A short note in your plan with a target word band and a sentence on scope keeps everyone aligned.
How To Size And Plan Your Chapter
Start With A Word Budget
Begin with the total thesis allowance from your handbook. Set a first pass budget across chapters, then assign the literature review a share inside the 20–40% band. Lock a minimum to protect synthesis space. Leave a small buffer so you can respond to supervisor edits without blowing past the cap.
Back It With A Scope Statement
Write three lines that set boundaries: core concepts, years included, and study types you will prioritize. Use that scope to accept or reject sources fast. Scope guards your length better than any target number.
Sample Budgets You Can Copy
Here’s a model that fits many health science PhD projects. Shift the shares to suit your method, but keep the review big enough to show synthesis, not just a list of summaries.
| Section | Share | Words |
|---|---|---|
| Introduction | 10% | 6,000 |
| Literature Review | 25% | 15,000 |
| Methods | 20% | 12,000 |
| Results | 25% | 15,000 |
| Discussion | 15% | 9,000 |
| Conclusion | 5% | 3,000 |
Build The Chapter In Layers
- Outline the map. Draft headings for concepts, methods, and debates that lead into your study aims.
- Synthesize, don’t stack. Compare findings, explain conflicts, and show where methods shape outcomes.
- End with a gap-to-aims bridge. Close by naming the gap and the exact way your study answers it.
How To Keep It Inside The Limit
Trim Moves That Save Words
- Move search details to an appendix if your program allows it.
- Replace long quotes with one-line paraphrases and citations.
- Group small related topics under one short subheading.
- Cut duplicate findings; cite once, synthesize once.
Expand Only Where It Adds Clarity
- Add brief method notes when study design explains result differences.
- Add definitions only when a term is contested or used in a special way.
- Add short tables to compress dense comparisons.
Signals You May Need More Or Less
- Too short: readers can’t see how your methods connect to prior work; debates feel under-developed.
- Too long: pages of study-by-study summary; aims repeat points from the review; methods restate background.
- Balanced: a clear map of themes, a reasoned gap, and a direct line into your research questions.
Common Length Mix-ups In Health Sciences
Counting Words The Right Way
Some schools count words in tables and captions; others exclude reference lists. Always check the small print in your handbook so you don’t undercount. Business schools at Leeds spell out that words in tables and figures count toward the cap, a policy many health schools mirror.
Systematic Review Chapters
When Chapter 2 is a full systematic review, the methods section inside that chapter can be long. Keep PRISMA items tight, push search strings and screening forms to an appendix where allowed, and link to your protocol if you have one. That way, you keep the core argument readable while meeting reporting norms.
Publishable Papers Theses
In a manuscript style thesis, the literature review lives in two places: a framing Chapter 1 and each paper’s introduction. Many programs ask for a fuller integrative introduction so the thesis reads as one program of work. Budget extra words in that opening chapter and keep each paper’s intro lean.
Quality Checks Before You Lock The Length
Read Three Recent Theses
Pick three dissertations from your program, ideally in your method and topic. Skim the contents pages, note the page spans for Chapter 2, and scan how they handled scope. This gives you a local norm you can match or bend with a reason.
Confirm With Your Advisor
Share a one-page plan with the chapter’s target share, an outline, and a one-line scope. Ask for a yes or a tweak. That five-minute check saves weeks later.
Run A Hard Edit
Read the chapter out loud. Cut any paragraph that only repeats a point you make better elsewhere. Merge micro-subheads that break the flow. Keep sentences short and active.
Examples By Research Design
Bench Or Lab Study
Scope is tight; major prior work clusters around a set of mechanisms or assays. A lean review that ties techniques to your aims often works.
Clinical Trial Or Intervention
Expect a longer chapter. Walk readers through prior trials, effect sizes, comparators, harms, and gaps. A short note on trial registries and bias helps readers weigh the field.
Qualitative Inquiry
The chapter spans theory, context, and method traditions. You may cite fewer sources than a scoping review but spend more words on concepts and how they frame your questions.
Public Health Evaluation
These projects pull from policy papers, surveillance data, and mixed-methods studies. Your review earns space by tracing how evidence travels into practice.
A Quick Way To Estimate Length
Pick a share in the 20–40% band, then do one clean sum: Total thesis limit × chosen share = target words. Keep a 10% buffer for edits and for late sources that sharpen your case. If your committee wants tighter bounds, set a floor and a ceiling and show both on your plan.
Worked Examples
- Masters, 15,000 total: choose 25% → plan 3,750 words; floor 3,200; ceiling 4,300.
- Doctorate, 70,000 total: choose 25% → plan 17,500 words; floor 15,000; ceiling 20,000.
Time Planning That Protects Quality
Block time in three passes. Pass one builds the map and bins sources. Pass two writes syntheses and tables. Pass three cuts words and tightens links to your aims. Short, regular sessions beat marathon weekends.
Keep Methods And Review In Sync
As your methods evolve, trim or expand the chapter so background and design match. If an objective drops, cut the thread that only served that goal. If a measure changes, add a short paragraph that shows where the choice comes from in the literature.
Clear Takeaway On Length
Plan the literature review as 20–40% of your thesis, then tune it to your degree level, review type, and local rules. Use a written scope to defend the space you need, and shape the chapter so it builds a clean bridge to your methods and aims. That balance keeps readers engaged and keeps you inside the limit your program sets. Let the handbook guide you always.