Physician performance, including evaluation of diagnostic errors, is often examined by conducting case reviews or root cause analyses when an undesired patient outcome occurs. This study analyzed case review data from a single emergency department over a 7-year period. Investigators found that physicians with more than 1.5 years of experience were less likely to make an error and that these errors were not associated with physician age. The authors argue for better methods for evaluating ongoing physician performance, including continuing medical education activities and certification (and recertification) requirements.