Systematic Reviews: Time to Address Clinical and Policy Relevance As Well As Methodological Rigor

Compared with other study designs, well-done random-ized trials provide the most valid estimate of the ben-efits of health interventions because they minimize bias. Systematic reviews of randomized trials identify all stud-ies that have addressed a particular question, and meta-analyses combine the results by using methods that mini-mize bias (1). Many consider systematic reviews to be the best source of information for making clinical and policy decisions. Such groups as the Cochrane Collaboration have es-tablished standards for the conduct and reporting of sys-tematic reviews (2). In this issue, Shojania and colleagues (3) extend this tradition of subjecting research methods to close scrutiny. They describe how quickly the conclusions of 100 systematic reviews published in ACP Journal Club became out of date because of newly completed random