The presence of outcome bias in emergency physician retrospective judgments of the quality of care.

Abstract

In peer review and malpractice litigation, biased assessment of the quality of care can have a profound effect. We determine the effect of knowledge of outcome on emergency physicians' ability to assess care quality. Emergency physicians completed a Web-based survey containing 6 case scenarios written to fall along a spectrum of quality of care. Participants were randomized to receive either no case outcomes or a mixture of good and bad outcomes. For each scenario, participants rated the quality of care categorically (poor, below average, average, good, outstanding) and on a 0- to 100-point scale. We examined how the scenario's outcome affected judgments about the quality of the process of care and whether certain individuals are more prone to outcome bias. Five hundred eighty-seven participants completed the survey. For each scenario, quality ratings were highest when the outcome was good and lowest when the outcome was bad. The difference between ratings for "good outcome" and "no outcome provided" was bigger than the difference between "no outcome provided" and "bad outcome." In cases of intermediate quality, outcome bias shifts ratings by a magnitude equivalent to 1 qualitative step in quality (eg, from good to average). The outcome bias effect is smaller for scenarios for which care is unambiguously good or bad. We found no evidence that outcome bias was concentrated in individuals. Emergency physicians demonstrate outcome bias in cases of intermediate quality more than in cases in which the quality of care is clear. Outcome bias tends to inflate ratings in the presence of a positive outcome more than it penalizes scenarios with negative ones.