Informational Frictions and Practice Variation: Evidence from Physicians in Training

Substantial practice variation across physicians for seemingly similar patients remains an unresolved puzzle. This paper studies physicians in training to explore the behavioral foundations of practice variation. A discontinuity in the formation of teams reveals a large contribution of relative experience in the size of practice variation. Among the same physician trainees, convergence towards a common practice differs by practice environment, with more convergence in specialist-driven services. Rich trainee characteristics and training histories, including the practice styles of prior supervising physicians, explain little if any variation. These findings suggest a major role for informational frictions in the origins of practice variation.