Invited Commentary| Volume 61, ISSUE 3, P207-208, March 2008

Randomized trials and observational studies: still mostly similar results, still crucial differences

      Although methodologists have long recognized that randomized trials provide stronger evidence than nonrandomized observational studies, for management decisions in which randomized trials are unavailable, clinicians and guideline developers must still rely on observational studies. Indeed, for a great many questions of clinical importance, observational studies constitute the best available evidence. In these situations, clinicians, guideline developers, and decision makers rightly expect guidance from methodologists in the use and interpretation of those studies and their integration into guideline recommendations.
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