Identification of meta-analyses. The need for standard terminology.

Our efforts to identify published articles describing meta-analyses of clinical trials illustrate the need for standard terminology to facilitate retrieval. We found 119 articles describing meta-analyses and eligible for inclusion in MEDLINE, and yet when we searched MEDLINE, using strategies based on textwords and medical subject headings (MeSH), only 48% of the 119 articles were identified. Sixty-eight (57%) of the 119 articles contained at least one of the terms "meta-analysis," "pooling," or "overview" in the title or abstract. The importance of meta-analyses in the evaluation of medical treatments argues for more disciplined use of a specific term in order to facilitate identification of articles. The fact that the National Library of Medicine has started in 1989 to index articles describing meta-analyses using the MeSH META-ANALYSIS underscores this argument.