The Institute of Medicine has suggested that training in team behavior, leadership, communication, and other human factors could reduce medical errors and improve patient safety. Training on such topics has been adapted from teamwork training programs used in military and commercial aviation, called crew resource management (CRM). The principles behind CRM programs have been deployed in a number of clinical settings over the past 2 decades, and there are now several CRM vendors. Little is known about this nascent industry, and the emerging research supporting CRM programs lacks standardization and conclusive evidence. The objectives of this study were to report on the body of empirical data about CRM training in clinical settings and to provide a conceptual framework for evaluating its effectiveness in medicine. Using the proposed conceptual framework, the authors further examine currently published methods of measuring effectiveness and identify future directions for the use of teamwork training in medicine.