Systematic Literature Review: A Step-by-Step PRISMA Guide for Researchers (2026)

A systematic literature review is the gold standard of evidence synthesis in academic research. Unlike a narrative review — which selects and interprets sources based on the author’s judgment — a systematic review follows a rigorous, pre-specified protocol designed to minimise bias and produce findings that are transparent, reproducible, and comprehensive. Whether you are conducting your first systematic review for a master’s dissertation or preparing a full Cochrane-style review for journal publication, this guide walks through every step using the PRISMA 2020 framework (Preferred Reporting Items for Systematic Reviews and Meta-Analyses).

Systematic reviews are now expected not just in clinical medicine but across health sciences, psychology, education, social policy, and management research. A 2024 analysis found that over 100,000 systematic reviews are published annually, making it the fastest-growing study design in academic literature. Understanding how to conduct — and critically appraise — a systematic review is an essential skill for any researcher in 2026.

What Is a Systematic Literature Review?

A systematic literature review is a secondary research study that identifies, appraises, and synthesises all available evidence on a defined research question using an explicit, reproducible methodology. Three features distinguish it from other review types:

• Pre-specified protocol: The methods are decided and ideally registered before the review begins, preventing post-hoc manipulation of results
• Comprehensive searching: Multiple databases are searched systematically to capture all relevant literature, including grey literature where appropriate
• Transparent reporting: Every decision — from search terms to inclusion criteria to quality appraisal — is documented and reported

The PRISMA statement, first published in 2009 and updated in 2020, provides the current reporting standard. PRISMA 2020 expanded the original 27-item checklist to address novel review types and improved guidance on risk of bias, certainty of evidence, and protocol registration.

Systematic vs Narrative vs Scoping Reviews

For a dissertation, a scoping or narrative review embedded in your literature review chapter is usually sufficient. A standalone systematic review as a dissertation is appropriate at master’s or doctoral level in health sciences, psychology, and education — and represents a significant, publishable piece of work.

Step 1: Define Your Research Question (PICO/PICo)

The quality of a systematic review is determined by the quality of its research question. An ill-defined question leads to an unmanageable search and unfocused synthesis. The PICO framework is the standard tool for structuring systematic review questions.

You must also define inclusion and exclusion criteria at this stage, covering: study design, language, publication date, population characteristics, and outcome measures. These criteria are applied consistently throughout the screening process.

Step 2: Register Your Protocol

Protocol registration is a distinguishing feature of a rigorous systematic review. Two primary registries exist:

• PROSPERO (prospero.york.ac.uk): The international register for health-related systematic reviews. Accepted by major journals as evidence of protocol registration.
• OSF Registries (osf.io): Open Science Framework preregistration, widely used in psychology and social sciences.

For a dissertation systematic review, full PROSPERO registration may not be required by your institution — check with your supervisor. However, writing a protocol document (even if not formally registered) disciplines your thinking and protects against unconscious bias in screening and synthesis.

Step 3: Develop Your Search Strategy

The search strategy is the technical heart of the systematic review. It translates your research question into database search syntax using a combination of controlled vocabulary terms (MeSH headings in MEDLINE; subject headings in other databases) and free-text keywords, connected by Boolean operators.

Boolean operators

• AND: Narrows the search (both terms must appear)
• OR: Broadens the search (either term may appear — used to combine synonyms)
• NOT: Excludes terms (use cautiously; may eliminate relevant records)

Have a subject librarian review your search strategy before running it. Most university libraries offer free search consultations for dissertation students — take advantage of this.

Step 4: Search Databases and Export Results

A systematic review should search a minimum of three to five databases to maximise retrieval. Standard databases by discipline:

Export all results to a reference manager (Zotero, Mendeley, or EndNote) and use the deduplication function to remove duplicates before screening begins. Record the number of results from each database — this feeds directly into your PRISMA flow diagram.

Step 5: Screen Titles and Abstracts

Title/abstract screening is the first filter. You apply your inclusion/exclusion criteria to the title and abstract only — without reading the full text. For large reviews, two independent reviewers screen each record and disagreements are resolved by consensus or a third reviewer. For a dissertation systematic review, one reviewer is common, but your supervisor may be able to serve as a second reviewer for a sample.

Use a tool like Rayyan (free, web-based) or Covidence (subscription, often available via university) to manage screening at scale. Record every exclusion decision so you can populate the PRISMA flow diagram accurately.

Step 6: Full-Text Eligibility Assessment

Studies that pass title/abstract screening are retrieved in full and assessed against the complete inclusion/exclusion criteria. This stage is more intensive — you read the methods, participants, and outcomes sections carefully. Record the reason for every exclusion (e.g., “wrong population,” “wrong outcome measure,” “not peer reviewed”) — PRISMA requires this information in the flow diagram.

Step 7: Data Extraction

For each included study, extract standardised data using a data extraction form designed before the review begins. Typical fields include:

• Author(s) and year
• Country and study setting
• Study design
• Sample size and participant characteristics
• Intervention or exposure (where applicable)
• Outcome measures and results
• Follow-up period
• Quality appraisal score
• Key findings relevant to your RQ

Step 8: Quality Assessment (Risk of Bias)

Systematic reviews must assess the methodological quality of included studies. The tool used depends on the study design:

• Randomised controlled trials: Cochrane Risk of Bias Tool 2 (RoB 2)
• Observational studies: Newcastle-Ottawa Scale (NOS)
• Qualitative studies: Critical Appraisal Skills Programme (CASP) checklist
• Mixed methods: Mixed Methods Appraisal Tool (MMAT)

Quality appraisal does not mean excluding lower-quality studies — it means contextualising findings within the strength of the evidence base. A finding from three high-quality RCTs is more certain than a finding from two small cross-sectional studies.

Step 9: Synthesis

Synthesis is where you combine findings from individual studies to answer your research question. Two approaches are used:

Narrative synthesis

Used when studies are too heterogeneous (different in design, population, or outcomes) to pool statistically. You describe patterns across studies thematically — grouping by outcome, population, or intervention type — and use evidence tables to present findings systematically. For qualitative synthesis, meta-ethnography (Noblit & Hare, 1988) or thematic synthesis (Thomas & Harden, 2008) are the most established approaches.

Meta-analysis

Used when three or more studies report comparable outcome data that can be pooled statistically. A meta-analysis calculates a pooled effect size with confidence intervals, accounting for study heterogeneity (measured by I² statistic). For a dissertation, meta-analysis is ambitious but achievable if your review is in a well-developed field with multiple comparable RCTs.

Step 10: PRISMA Flow Diagram and Reporting

The PRISMA 2020 flow diagram visualises the four phases of your review:

1. Identification: Total records identified (across all databases + other sources), minus duplicates removed
2. Screening: Records screened at title/abstract level; records excluded at this stage
3. Eligibility: Full-text articles assessed; reasons for exclusion listed
4. Inclusion: Studies included in the review; studies included in meta-analysis (if applicable)

Free PRISMA flow diagram generators are available at prisma-statement.org. The PRISMA 2020 checklist is published in open-access form in BMJ, Systematic Reviews, and several other journals.

Recommended Tools and Software

For research methodology background, our qualitative research methods guide and research methodology types overview provide essential context. For managing your literature, see our Google Scholar advanced search techniques guide.

Frequently Asked Questions