Reporting

Phase 5: Write up the review

Writing up is the public face of the review. Peer reviewers, clinicians, policymakers, and future evidence synthesists all rely on what you publish to judge trustworthiness and to decide whether to update the review. Modern journals and funders increasingly require compliance with a write-up guideline (PRISMA, PRISMA-ScR, MOOSE) and registration of the protocol on PROSPERO or a similar registry. This phase closes the loop that started with your search strategy.

1. Register the protocol (PROSPERO)

PROSPERO (National Institute for Health Research, University of York) is the international prospective register for systematic reviews in health, social care, welfare, public health, education, crime, justice, and international development. Registration is free and should happen before screening starts.

Registration records:

• Review question and objectives.
• PICO and eligibility criteria.
• Information sources and search strategy.
• Study selection and data extraction procedures.
• Risk of bias and synthesis methods.
• Dates, team, funding, amendments.

Once registered, PROSPERO issues a registration number you cite in the manuscript. Non-health reviews may register with the Open Science Framework (OSF) or the Campbell Collaboration. Scoping reviews are not registered on PROSPERO but can be posted as pre-prints on OSF or Figshare.

2. PRISMA 2020: 27-item checklist

PRISMA 2020 (Page et al., BMJ 2021) is the current write-up standard for systematic reviews and meta-analyses. It contains 27 items across seven sections.

Title and abstract (items 1 and 2).

1. Identify as a systematic review.
2. Structured abstract following PRISMA for Abstracts.

Introduction (items 3 and 4).

3. Rationale for the review in the context of existing knowledge.
4. Explicit objectives or questions with PICO elements.

Methods (items 5 through 15).

5. Eligibility criteria and how studies were grouped for the synthesis.
6. Information sources (databases, registers, grey literature) and last search date.
7. Full search strategies for all databases (PRISMA-S).
8. Selection process and number of reviewers per step.
9. Data collection process (extraction) and number of reviewers.
10. Data items: outcomes and other variables extracted.
11. Risk of bias assessment, including tool and number of assessors.
12. Effect measures (RR, OR, SMD, HR) for each outcome.
13. Synthesis methods including handling of missing data, heterogeneity, and subgroup analyses.
14. Bias-in-the-literature assessment.
15. Certainty assessment (GRADE).

Results (items 16 through 22).

16. Study selection with a PRISMA flow diagram.
17. Study characteristics table.
18. Risk of bias results.
19. Results of individual studies.
20. Results of syntheses (pooled estimates, heterogeneity, forest plots).
21. Biases in the literature.
22. Certainty of evidence (Summary of Findings table).

Discussion (items 23 through 26).

23. General interpretation, including applicability.
24. Limitations of included studies and of the review process.
25. Implications for practice, policy, and future research.
26. Registration and protocol details, including deviations.

Other information (item 27).

27. Support, competing interests, and availability of data, code, and other materials.

The full PRISMA 2020 checklist, the PRISMA 2020 for Abstracts checklist, and the PRISMA-S search-write-up extension are all available via the EQUATOR Network. Complete the checklist as you write, not retrospectively.

3. PRISMA-ScR for scoping reviews

Scoping reviews follow PRISMA-ScR (Tricco et al., 2018), a 20-item extension of PRISMA tuned to the broader, descriptive aims of scoping work. It drops synthesis-specific items (effect measures, certainty) and adds items on mapping and charting. Use PRISMA-ScR when writing up any review that follows the scoping review methodology.

Other write-up extensions worth knowing:

• PRISMA-IPD for individual patient data meta-analyses.
• PRISMA-NMA for network meta-analyses.
• PRISMA-Equity for equity-focused reviews.
• MOOSE for meta-analyses of observational studies.
• ENTREQ for qualitative evidence syntheses.
• RAMESES for realist and meta-narrative reviews.

4. The PRISMA flow diagram

The flow diagram is the mandatory visual of any PRISMA-compliant review. It shows how records moved from identification through screening, eligibility, and inclusion, with exclusion reasons at the full-text stage.

Every number in the diagram must match your screening phase exports. The PRISMA Flow Diagram Template is an editable PDF/Word/PowerPoint file available in the templates library.

5. Manuscript structure (IMRaD)

Most review manuscripts follow a conventional IMRaD structure.

• Title names the review type ("A systematic review and meta-analysis of ...").
• Structured abstract covers Background, Methods, Results, Conclusions, Registration.
• Introduction covers rationale, knowledge gap, objectives, and the review question with PICO.
• Methods covers protocol and registration, eligibility criteria, information sources, search strategy (PRISMA-S), selection process, data extraction, risk of bias, effect measures, synthesis methods, and certainty assessment.
• Results covers study selection (PRISMA flow), study characteristics, risk of bias, synthesis results (forest plots, theme maps), biases in the literature, and certainty (SoF table).
• Discussion covers summary of evidence, applicability, limitations of evidence and of review process, and implications for practice and research.
• Other covers funding, competing interests, author contributions, data availability, and supplementary materials (full search strategies, extraction forms, analysis code, PRISMA checklist).

6. Common write-up pitfalls

• Missing search date or database versions. Makes the review non-reproducible.
• PRISMA flow diagram counts that do not reconcile. Reviewers will notice.
• Failure to record full-text exclusion reasons. Violates PRISMA 2020 item 16.
• Unregistered protocol with post-hoc changes. Permissible only if deviations are explicitly logged.
• No certainty assessment. GRADE (or CERQual) is now standard.
• Appendix dumps instead of structured supplements. Organise search strategies, extraction forms, and code as clearly labelled files.
• Narrative sections written first, methods retrofitted. Write methods while you do them.

7. Publishing and preservation

• Deposit your data, code, and extraction forms in a public repository (OSF, Zenodo, Figshare) with a DOI.
• Cite your PROSPERO registration number in the abstract and methods.
• Plan the update cycle. Living systematic reviews use continuous search and synthesis; even "one-off" reviews benefit from a scheduled update at 24 to 36 months.

Tools and templates for this phase

• PRISMA Flow Diagram Template — editable, PRISMA 2020-compliant.
• Search Strategy Documentation Form — becomes your PRISMA-S supplement.
• Related review types: systematic reviews, scoping reviews, and meta-analyses.

The review process, end to end

You have now moved a research question through search, screening, extraction, synthesis, and write-up. Revisit the process hub when you update the review, and return to Phase 1 — Search Strategy to re-run the search before any update.