Synthesizing evidence: Shifting the focus from individual studies to the body of evidence

摘要

THE RESEARCH ENTERPRISE BEHAVES AS IF A SINGLE study could provide the ultimate answer to a clinical question. Researchers offer overoptimis-tic sample-size calculations and other design features to convince funders and institutional review boards that their study will provide the answer. Medical journals and the popular media highlight single studies, too often without regard to similar studies. Only a small proportion of trials have been synthesized into systematic reviews. Researchers with the Cochrane Centre have advocated for the results of individual studies to be placed in the context of the totality of evidence for the last 15 years, with limited success. With more empirical evidence supporting this view, we offer 5 reasons to shift the collective focus from single studies to the accumulating body of evidence.