Increasing number of databases searched in systematic reviews and meta-analyses between 1994 and 2014.
OBJECTIVE
The purpose of this study was to determine whether the number of bibliographic databases used to search the health sciences literature in individual systematic reviews (SRs) and meta-analyses (MAs) changed over a twenty-year period related to the official 1995 launch of the Cochrane Database of Systematic Reviews (CDSR).


METHODS
Ovid MEDLINE was searched using a modified version of a strategy developed by the Scottish Intercollegiate Guidelines Network to identify SRs and MAs. Records from 3 milestone years were searched: the year immediately preceding (1994) and 1 (2004) and 2 (2014) decades following the CDSR launch. Records were sorted with randomization software. Abstracts or full texts of the records were examined to identify database usage until 100 relevant records were identified from each of the 3 years.


RESULTS
The mean and median number of bibliographic databases searched in 1994, 2004, and 2014 were 1.62 and 1, 3.34 and 3, and 3.73 and 4, respectively. Studies that searched only 1 database decreased over the 3 milestone years (60% in 1994, 28% in 2004, and 10% in 2014).


CONCLUSIONS
The number of bibliographic databases searched in individual SRs and MAs increased from 1994 to 2014.
Michael T
MT
Lam
Mary
M
McDiarmid
D016206:Databases, Bibliographic / Q000706:statistics & numerical data*; D019317:Evidence-Based Medicine / Q000379:methods / Q000706:statistics & numerical data; D006801:Humans; D015201:Meta-Analysis as Topic; D012196:Review Literature as Topic
Database, Bibliographic; Databases as Topic; Evidence-based Medicine; MEDLINE; Review