Competency-based medical education (CBME) aims to bring about the sequential acquisition of competencies required for practice. Although it is being adopted in centers of medical education around the globe, there is little evidence concerning whether, in comparison with traditional methods, CBME produces physicians who are better prepared for the practice environment and contributes to improved patient outcomes. Consequently, the authors, an international group of collaborators, wrote this article to provide guidance regarding the evaluation of CBME programs.CBME is a complex service intervention consisting of multiple activities that contribute to the achievement of a variety of outcomes over time. For this reason, it is difficult to apply traditional methods of program evaluation, which require conditions of control and predictability, to CBME. To address this challenge, the authors describe an approach that makes explicit the multiple potential linkages between program activities and outcomes. Referred to as contribution analysis (CA), this theory-based approach to program evaluation provides a systematic way to make credible causal claims under conditions of complexity. Although CA has yet to be applied to medical education, the authors describe how a six-step model and a postulated theory of change could be used to examine the link between CBME, physicians' preparation for practice, and patient care outcomes.The authors argue that adopting the methods of CA, particularly the rigor in thinking required to link program activities, outcomes, and theory, will serve to strengthen understanding of the impact of CBME over time.
