Evidence based? Caveat emptor!

Medical practices, clinical practice guidelines, clinical performance measures and measurements, and a variety of health care-related administrative decisions, such as insurance coverage decisions, are claiming to be "evidence based" with increasing frequency. In this paper we examine the "evidence based" label; discuss how evidence ought to have been assembled, evaluated, and synthesized; and when evidence is sufficient for the "evidence-based" moniker to rightfully apply. We also highlight several considerations other than the strength of evidence that are relevant to several common types of health care-related administrative decisions and that influence the extent to which the resulting decisions are truly evidence based.