Search for existing reviews and protocols
Before you begin any evidence synthesis project, it’s a good idea to see if your question has already been addressed. Looking at existing evidence synthesis on similar topics can also be a useful way to refine your question or consider how you might approach your topic. Below are some resources you may want to consider that can offer streamlined access to evidence syntheses:
- Cochrane Library
- Joanna Briggs Library
- PROSPERO
- OSF Registries and OSF.io projects
- TRIP Database
- Systematic Reviews for Animals & Food (SYREAF)
- Campbell Collaboration
- Health Evidence
- Epistemonikos
- 3iE Database
- Community Guide
- EPPI-Centre
- Collaboration for Environmental Evidence
- International HTA Database
- Preprint servers
- BEME: Best Evidence Medical and Health Professional Education
Tools for evaluating existing reviews
Even if you find an evidence synthesis on exactly your question, that doesn’t necessarily mean that it was done in a methodologically rigorous way. Unfortunately, not everything that’s published is of the highest quality. Fortunately, there are some resources specifically developed to help you assess the quality of evidence syntheses.
Updating existing reviews
Even methodologically rigorous reviews may be in need of an update.
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Garner, P., Hopewell, S., Chandler, J., MacLehose, H., Schünemann, H., Akl, E., . . . Wilson, E. (2016). When and how to update systematic reviews: Consensus and checklist. BMJ, 354, I3507.