Ensuring the competence of the 17 000 practicing physicians in the Canadian province of Ontario has occupied more than a decade of activity on the part of the provincial licensing authority, the College of Physicians and Surgeons of Ontario (CPSO).1 While still in a developmental stage, the provincial peer review system places importance on (and thus provides an opportunity to test models of) physician assessment, learning, and change. The peer review system was initially developed in the mid1970s. At that time, peer review policymakers viewed continuing medical education (CME) activities in a narrow, but appropriately critical, light and rejected compliance with mandatory CME requirements as a measurement of physician competence. This action reflected the belief that most CME programs failed to change physician performance. Studies conducted since that time concluded that formal CME courses do produce knowledge transfer2-6; but without reinforcement, feedback, or other behavior modification techniques, CME