Simulation was initially used in health care as a tool for teaching clinical skills, but it is increasingly being used as a component of teamwork training. Although a recent systematic review found that simulation methods are effective (compared with traditional didactic teaching) at improving learners' skills and behaviors, their effect on patient care remains unclear. This systematic review identified 38 studies—most of which used simulation to teach procedural skills—that examined the effect of simulation training on patient-level outcomes and found evidence that simulation improves team behaviors, procedural competence, and patient care outcomes. This study was funded by the Agency for Healthcare Research and Quality as part of the Making Health Care Safer II report and was published as part of a special patient safety supplement in the Annals of Internal Medicine. An AHRQ WebM&M perspective and interview discuss the role of technology in simulation and the characteristics of optimal simulation exercises.