Teamwork is a vital skill for health care professionals, but the fragmented systems within which they work frequently do not recognize or support good teamwork. The American Board of Internal Medicine has developed and is testing the Teamwork Effectiveness Assessment Module (TEAM), a tool for physicians to evaluate how they perform as part of an interprofessional patient care team. The assessment provides hospitalist physicians with feedback data drawn from their own work of caring for patients, in a way that is intended to support immediate, concrete change efforts to improve the quality of patient care. Our approach demonstrates the value of looking at teamwork in the real world of health care-that is, as it occurs in the actual contexts in which providers work together to care for patients. The assessment of individual physicians' teamwork competencies may play a role in the larger effort to bring disparate health professions together in a system that supports and rewards a team approach in hope of improving patient care.