Cochrane Central Register of Controlled Trials
Appraisal of: “Banno M, Tsujimoto Y, Kataoka Y. Using the Cochrane Central Register of Controlled Trials to identify clinical trial registration Is insufficient: a cross-sectional study. BMC Med Res Methodol. 2020, 20: 200”
The CENTRAL (Cochrane Central Register of Controlled Trials) database (available via The Cochrane Library) is a source of randomized and quasi-randomized controlled trials. CENTRAL is populated from multiple database sources, including clinical trial registries such as ClinicalTrials.gov and ICTRP. This study aimed to investigate whether searching CENTRAL alone was sufficient for identifying ongoing and unpublished studies.
The authors created a set of clinical trials registrations included in a sample of 50 Cochrane reviews published in 2019. The authors tested whether the search strategies for CENTRAL documented in these reviews would retrieve all the included clinical trial registrations.
Searches of CENTRAL database with the documented Cochrane review search strategies identified only 200 of the 247 clinical trial registrations. All 47 of the unidentified studies were registered in either ClinicalTrials.gov or ICTRP. 16 of these studies were not indexed in CENTRAL.
The authors conclude that ClinicalTrials.gov and ICTRP should be searched in addition to CENTRAL.
Appraisal of: Craven J, Jefferies J, Kendrick J, Nicholls D, Boynton J, Frankish R. A comparison of searching the Cochrane library databases via CRD, Ovid and Wiley: implications for systematic searching and information services. Health Info Libr J. 2014
The different interfaces for searching Cochrane Library databases are compared in this paper. Firstly CENTRAL and CDSR are compared via Ovid and Wiley and then DARE, NHS EED and HTA databases are compared via Ovid, Wiley and the CRD website. The authors explore search syntax comparisons including proximity operators, MeSH headings, search term order and fields searched. The authors found that there were differences in the use of MeSH headings, searching for free text and using proximity operators. They also suggest a “best match” search syntax to be used across the different interfaces.
