Systematic review without meta-analysis
What does the evidence show when pooling is unsuitable or not planned?
When to use this project
Use this starter for a systematic review with explicit selection and appraisal, but a structured synthesis without a pooled effect. The reasons may differ by outcome: incompatible measures, missing effect statistics, or substantively different interventions.
How it differs
This remains an answer-focused systematic review. It is not a scoping review merely because it lacks a meta-analysis. “Narrative synthesis” alone is not a reproducible method description.
Decisions before you start
- Define synthesis groups and the rule for selecting one result when a study reports several relevant results.
- Describe exactly how effects, uncertainty and study limitations will be compared; include a study-level evidence table.
- Do not count statistically significant versus nonsignificant results as votes for or against an effect. Document the limitations of any direction-based summary.
How the flows work together
Each flow below links to its diagram, steps and tables. Flow order organizes the project; it does not imply that all work is strictly sequential. Data assessment, analysis planning and protocol refinement may inform one another.
1. Review overview
Overview · Question through structured synthesis
Use this overview to state the purpose and link to detailed decisions. Keep a versioned protocol and decision register, and add evidence references for the rationale.
2. Search and study selection
Selection · Identify and screen eligible studies
Keep records, reports and studies as separate counting units. The starter partition covers duplicate removal only: add explicit branches for automation or other removals if used. Supplementary searches may need separate identification routes. A final report-to-study mapping is not an exclusion count.
3. Extraction and structured synthesis
Data · Group and summarize eligible evidence
This flow is structured synthesis of quantitative evidence. A qualitative evidence synthesis needs different analytic methods; it is not automatically supplied by this starter. Preserve effect magnitude and uncertainty where available.
4. Bias and evidence certainty
Statistics · Assess limitations and confidence
A review without pooling still needs transparent appraisal and interpretation. Choose a certainty approach appropriate to the review question; do not invent a pooled effect or numerical certainty score.
Equations and statistical interpretation
These explanations describe notation and assumptions. Flow does not calculate these values.
No mandatory pooled-effect equation
No pooled estimate required
Preserve each study’s effect measure, denominator, follow-up and interval in the extraction table.
Do not manufacture a pooled estimate to fill a template. Select a defensible alternative synthesis method and state what question it can answer.
Published example
The authors report use of the SWiM checklist. Use its synthesis and reporting choices as a concrete example, not as a universal model for all reviews without pooling.
This publication illustrates a study design, not an endorsement of every method or a reproduction of its results. Follow its protocol, supplement and update history when studying the example.
Hypothetical scenario
A primary-care team wants to understand whether AI-supported medication management reduces medication errors, but studies use incompatible error definitions and report different effect statistics.
- Review overview: Define eligible systems, care settings and medication-safety outcomes in a protocol.
- Search and study selection: Search and select studies systematically; retain a study-to-report crosswalk.
- Extraction and structured synthesis: Group studies by task and outcome, tabulate their estimates and uncertainty, and document why each group is not pooled.
- Bias and evidence certainty: Interpret patterns alongside risk of bias and missing evidence; distinguish lack of evidence from lack of benefit.
Deliver a populated protocol, decision log, data specification, and planned outputs. Enter numerical findings only after analysis and verification. Keep decisions made before seeing results distinguishable from later amendments.
Sources
- Cochrane Handbook, Chapter 12: Other synthesis methods
- SWiM reporting guideline (Campbell et al., 2020)
- PRISMA 2020 reporting guidance
- PRISMA 2020 flow diagrams: identification and selection
- Cochrane Handbook, Chapter 14: Certainty and Summary of findings
Source check: 2026-09-17. Record the version of each reporting or appraisal tool used in your actual protocol.
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