Authors: Carol Lefebvre, Eric Manheimer and Julie Glanville on behalf of the Cochrane Information Retrieval Methods Group.
Key points
Review authors should work closely from the start with the Trials Search Co-ordinator (TSC) of their Cochrane Review Group (CRG).
Studies (not reports of studies) are included in Cochrane reviews but identifying reports of studies is currently the most convenient approach to identifying the majority of studies and obtaining information about them and their results.
Trials registers and trials results registers are an increasingly important source of information.
The Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE and EMBASE (if access is available to either the review author or TSC) should be searched for all Cochrane reviews, either directly or via the CRG’s Specialized Register.
Searches should seek high sensitivity, which may result in relatively low precision.
Too many different search concepts should be avoided, but a wide variety of search terms should be combined with OR within each concept.
Both free-text and subject headings should be used (for example Medical Subject Headings (MeSH) and EMTREE).
Existing highly sensitive search strategies (filters) to identify randomized trials should be used, such as the newly revised Cochrane Highly Sensitive Search Strategies for identifying randomized trials in MEDLINE (but do not apply these filters in CENTRAL).
6.3 Planning the search process
6.4 Designing search strategies
6.6 Documenting and reporting the search process
Box 6.7.a: The Cochrane Information Retrieval Methods Group