Reporting guidelines help to ensure quality, consistency and transparency in scientific publications – however, they are not yet available for all types of study or analysis. For example, the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines may be insufficient when data unsuitable for meta-analysis necessitate alternative synthesis methods. Currently, a lack of transparency can leave readers questioning the validity of findings from such analyses, yet this is crucial given that approximately one third of health-related systematic reviews, key to informing healthcare policy, use such methods. The Synthesis Without Meta-analysis (SWiM) guidelines, developed by experienced systematic reviewers and released earlier this year, aim to provide clarity for reporting these important analyses.
The nine-item SWiM checklist for reporting systematic reviews using alternative synthesis methods is intended to be used as an extension to PRISMA.
Key elements are to describe:
- groups used in the synthesis (with a rationale)
- standardised metrics for each outcome and any transformation methods
- synthesis methods
- any criteria used to prioritise results from different studies, for the synthesis or conclusions, with justification
- method(s) used to examine heterogeneity in reported effects
- methods used to assess certainty of the synthesis findings
- graphical and tabular methods used to present the findings and key characteristics used to order the studies
- synthesised findings for each comparison and outcome, and the certainty of those findings
- limitations of the synthesis methods and/or groupings used, and the impact on the conclusions that can be drawn.
While SWiM Principal Investigator Dr Hilary Thomson noted that the guidelines have not been able to address everything captured by the ambiguous term ‘narrative synthesis’, she hopes that they increase transparency in reporting and stimulate further discussion. To learn more about the guidelines, why not access webinars and further resources, or get involved in discussing good practice via the SWiM network.