How to Do a Systematic Literature Review: PhD Guide (2026)
Meet the Expert
Shruti Sharma
Academic Writing Coach & Systematic Review Specialist
- Guided 80+ PhD scholars through systematic and scoping literature reviews
- Expert in PRISMA protocol, database searching strategies, and evidence synthesis
- Specialises in literature review methodology across health, education, and social sciences
A systematic literature review is the most rigorous form of literature review in academic research. Unlike a traditional narrative review, it follows a transparent, reproducible protocol to identify, screen, and synthesise all relevant evidence on a specific research question. Mastering systematic review methodology is increasingly essential for PhD scholars in health, social sciences, and education.
Systematic Review vs Narrative Review: Key Differences
| Aspect | Systematic Literature Review | Narrative Literature Review |
|---|---|---|
| Purpose | Answer a specific, focused question | Survey the field broadly |
| Protocol | Pre-defined, registered protocol (PRISMA) | No formal protocol required |
| Search Strategy | Comprehensive, documented, reproducible | Selective, often not documented |
| Inclusion Criteria | Explicit, pre-defined | Informal, author-determined |
| Quality Assessment | Formal quality appraisal tools | Usually absent |
| Synthesis | Systematic (meta-analysis or narrative synthesis) | Narrative summary |
| Replicability | High — another researcher would reach the same result | Low — depends on author choices |
Step-by-Step: How to Conduct a Systematic Literature Review
Step 1: Formulate Your Review Question
Your review question must be specific and answerable. Use the PICO (Population, Intervention, Comparison, Outcome) framework for health/clinical reviews, or SPIDER (Sample, Phenomenon of Interest, Design, Evaluation, Research type) for qualitative reviews. A well-formulated question guides all subsequent decisions.
Example: 'What is the effect of mindfulness-based interventions on academic stress levels among postgraduate students?'
Step 2: Develop and Register Your Protocol
Before searching, document your review protocol: the research question, eligibility criteria, databases to be searched, search terms, and planned analysis. Consider registering your protocol on PROSPERO (for health/social science reviews) or Open Science Framework (OSF) to demonstrate pre-registration.
Step 3: Conduct the Database Search
Search multiple databases using a structured search string combining keywords, Boolean operators (AND, OR, NOT), and database-specific subject headings (MeSH terms in PubMed, Emtree in Embase).
| Field | Recommended Databases |
|---|---|
| Health/Medicine | PubMed, Embase, Cochrane Library, Web of Science |
| Social Sciences | Scopus, Web of Science, PsycINFO, JSTOR |
| Education | ERIC, British Education Index, Scopus, EBSCO |
| Management/Business | Scopus, Web of Science, ABI/Inform, EBSCO Business |
| All Fields | Google Scholar (supplementary), Grey literature sources |
Step 4: Screen Studies Using Inclusion/Exclusion Criteria
Apply your pre-defined eligibility criteria in two stages:
- Title and abstract screening — Review titles and abstracts of all retrieved results against your criteria
- Full-text screening — Obtain and review full texts of potentially eligible studies
Use reference management software (Zotero, Mendeley, Rayyan) to manage and deduplicate results. For rigour, two reviewers should independently screen studies, with disagreements resolved by discussion or a third reviewer.
Step 5: Assess Quality of Included Studies
Appraise the methodological quality of included studies using appropriate tools:
- RCTs: Cochrane Risk of Bias Tool (RoB 2)
- Observational studies: Newcastle-Ottawa Scale
- Qualitative studies: CASP (Critical Appraisal Skills Programme) Checklist
- Mixed methods: Mixed Methods Appraisal Tool (MMAT)
Step 6: Extract Data
Use a standardised data extraction form to record key information from each included study: author, year, setting, sample, intervention/phenomenon, methods, key findings, and quality score. This can be done in Excel, Rayyan, or specialist software like Covidence.
Step 7: Synthesise the Evidence
Depending on the studies' comparability, use either:
- Meta-analysis — Statistical pooling of quantitative data (requires sufficient homogeneity)
- Narrative synthesis — Structured textual summary when statistical pooling is not appropriate
- Thematic synthesis — For qualitative evidence
- Framework synthesis — Mapping evidence onto a theoretical framework
Step 8: Report Using PRISMA 2020
Follow the PRISMA 2020 checklist and include the PRISMA flow diagram showing the number of records identified, screened, assessed for eligibility, and included. Most journals and examiners now expect PRISMA-compliant reporting for systematic reviews.
Time-Saving Tip for PhD Students
Use Rayyan (free online tool) for collaborative title/abstract screening. Use Zotero for reference management and deduplication. Register your protocol on PROSPERO before you begin searching — this demonstrates rigour and protects against accusations of post-hoc protocol changes.
Need expert support with your systematic literature review? Thesis Ace Writers provides end-to-end systematic review support — from protocol development to evidence synthesis and PRISMA-compliant reporting.
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Frequently Asked Questions
Click a question to expand the answer.
A systematic literature review (SLR) is a rigorous, reproducible method of identifying, evaluating, and synthesising all relevant research on a specific question. Unlike a narrative literature review, it follows a pre-defined protocol (often PRISMA), uses explicit inclusion/exclusion criteria, searches multiple databases systematically, and documents every decision — making the process transparent and replicable.
PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) is the most widely used reporting guideline for systematic reviews. The PRISMA 2020 checklist has 27 items covering: title, abstract, introduction, methods (eligibility, information sources, search, selection, data extraction, quality assessment), results (study selection, study characteristics, synthesis), and discussion. The PRISMA flow diagram visually shows how studies were identified, screened, and included.
A rigorous systematic review should search at least 3–5 major databases relevant to your field. Common databases include: Scopus, Web of Science, PubMed (health sciences), PsycINFO (psychology), ERIC (education), EBSCO, and Google Scholar as a supplementary source. You should also check reference lists of included studies (backward citation search) and search grey literature if relevant.
A systematic review aims to answer a specific, focused question by exhaustively synthesising evidence — often including quality assessment and meta-analysis. A scoping review maps the extent and nature of evidence on a broader topic, identifies key concepts and gaps, and does not usually include quality assessment. Scoping reviews are more appropriate when the field is new or the evidence base is heterogeneous.
Yes — in health sciences, medicine, and increasingly in social sciences and education, PhD theses based entirely on systematic reviews (including meta-analyses) are accepted. The PhD student demonstrates doctoral-level skills through the rigour of the review process, the quality of evidence synthesis, and the interpretive contribution. Check your university's requirements and discuss with your supervisor.