It looks like you're using Internet Explorer 11 or older. This website works best with modern browsers such as the latest versions of Chrome, Firefox, Safari, and Edge. If you continue with this browser, you may see unexpected results.
Systematic Reviews and Meta Analysis
A resource for finding data sources, filters, and standards to support systematic searches of the biomedical literature.
Clinical trials make up a much larger body of literature than do randomized trials. Also, authors have a bewildering number of ways of referring to clinical trials, making searching for them a particular challenge. If you wish to included non-randomized trials in your review or analysis, it is best not to limit. If you must, clinical trials will be retrieved as part of the PubMed Clinical Queries sensitive search:
("clinical"[tiab] AND "trial"[tiab]) OR "clinical trials as topic"[mesh] OR "clinical trial"[pt] OR random*[tiab] OR "random allocation"[mesh] OR "therapeutic use"[sh]
A broader strategy, modified slightly from , can be used:
"randomized controlled trial"[pt] OR "controlled clinical trial"[pt] OR "clinical trials as topic"[mesh] OR "random allocation"[mesh] OR "double-blind method"[mesh] OR "single-blind method"[mesh] OR "clinical trial"[pt] OR "research design"[mesh:noexp] OR "comparative study"[pt] OR "evaluation studies"[pt] OR "follow-up studies"[mesh] OR "prospective studies"[mesh] OR "cross-over studies"[mesh] OR "clinical trial"[tw] OR ((singl*[tw] OR doubl*[tw] OR trebl*[tw]) AND (mask*[tw] OR blind*[tw])) OR placebo*[tw] OR random*[tw] OR "control"[tw] OR "controls"[tw] OR prospectiv*[tw] OR volunteer*[tw]
This strategy was reported to have greater than 99% sensitivity on a small test set. The precision was not reported, though it must be about 13%, which is approximate precision of the Clinical Queries hedge.
1. Robinson KA, Dickersin K. Development of a highly sensitive search strategy for the retrieval of reports of controlled trials using PubMed. Int J Epidemiol. 2002 Feb;31(1):150-3. PubMed PMID: 11914311.