When do clinical decision rules improve patient care?

Holmes et al1 remark that decision rules "aid and empower clinicians by providing evidence with regard to risk"; however, the devil is in the details of application. Their particular new decision rule, if successfully validated, may reduce abdominal CT scanning by up to 11% in settings wherein committed clinicians can selectively and consistently apply the rule in a1-way fashion. Elsewhere, however, the rule may be perceived as too complex, insufficiently sensitive, less accurate than gestalt, and having the potential to increase rather than decrease CT usage. Penaloza et al2 make a compelling case that skilled clinicians should likely abandon 2 common decision rules for pulmonary embolism risk stratification because they are inferior to gestalt. Meltzer et al3 disprove a widely described scoring system for appendicitis in adults. Decision rules are everywhere in medicine today but often add little or nothing to solid professional judgment. Before we adopt them, we should carefully scrutinize the strengths and limitations of each.