Searching for Evidence

To answer key questions and guide evidence-based practice, it is optimal to identify all available relevant better quality studies or valid and up-to-date syntheses of such studies. In recent years, much work has been devoted to developing effective search strategies to reach these ends. A good search strategy will identify a high proportion of available relevant studies without requiring us to sift through much irrelevant material. Below you will find selected key resources on this topic.

"Online source" indicates that the resource is available online without charge. Cost-free registration may be required for access to some items with this designation.

In addition to more effective searching of the general databases, searchers can consult The Cochrane Database of Systematic Reviews and other specialized databases of syntheses of better evidence.

Identifying better studies: general guides
Identifying better primary studies: Cochrane CENTRAL Register
Identifying systematic reviews and meta-analyses

Identifying better studies: general guides

Finding studies for systematic reviews: a resource list for researchers, Centre for Reviews and Dissemination.

Finding the evidence
, Centre for Evidence Based Medicine.

Golder S. Search strategies to identify information on adverse effects: a systematic review. J Med Lib Assoc. 2009;97(2):84-92.
(Online Source, PDF)

Haynes RB, McKibbon KA, Wilczynski NL, Walter SD, Were SR, for the Hedges Team. Optimal search strategies for retrieving scientifically strong studies of treatment from Medline: analytical survey. BMJ. 2005;330(7501):1179.
(Online Source)

InterTASC information specialists’ sub-group search filter resource, Centre for Reviews and Dissemination.

Lefebvre C, Manheimer E, Glanville J, on behalf of Cochrane Information Retrieval Methods Group. Chapter 6: Searching for Studies. In: Higgins JTP, Green S, eds. Cochrane Handbook for Systematic Reviews of Interventions, Version 5.0.2, updated September 2009.
(Online Source)

PubMed clinical queries, National Library of Medicine.

Identifying better primary studies: Cochrane CENTRAL Register

The Cochrane Central Register of Controlled Trials (CENTRAL), Cochrane Collaboration.
(Online source for initial search results to about 500,000 records, primarily of controlled trials)
(Online source for Ovid search guide)

Dickersin K, Manheimer E, Wieland S, Robinson KA Lefebvre C, McDonald S. Development of the Cochrane Collaboration's CENTRAL Register of Controlled Clinical Trials. Eval Health Prof. 2002;25(1):38-64.

Identifying systematic reviews and meta-analyses

PubMed clinical queries: find systematic reviews, National Library of Medicine.

Systematic reviews, Information Sources, Centre for Reviews and Dissemination

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Most recent page update: 1/31/2011