LTHOUGH different modes of transport, such as aviation and rail, have become increasingly safer over the past 20 years, accidents still occur. 1 Similarly, adverse outcomes occur in healthcare, despite numerous improvements in areas such as, for example, selection and training of personnel, design and maintenance of equipment, and greater availability and reduced side effects of many drugs. 2 However, the proportional gains in aviation have been larger than those in healthcare, and, if for this reason alone, the Institute of Medicine Report, 'To Err is Human,' 3 recommended that medicine adopt aviation's approaches to safety and error management. 4 S Si im mi il la ar ri it ti ie es s b be et tw we ee en n a av vi ia at ti io on n a an nd d h he ea al lt th hc ca ar re e There are similarities in the ongoing struggle for safety in both healthcare and aviation. First, although safety is the primary goal, cost drives decisions. Second, both domains have, in part, become safer because of technological innovation. Third, there are multiple sources of threats to safety in both systems-technological, human, and environmental. Fourth, disasters are always followed by furious bouts of second-guessing. Fifth, teamwork is essential in reducing, trapping and mitigating or treating errors. 5-7 This last point demands further elaboration. Most endeavors in healthcare, science, and industry require groups to work together effectively-this is the essence of teamwork. Failures of teamwork in complex organizations can have deadly effects. More than twothirds of air crashes involve human or pilot error as a primary factor, in contrast to the decreasing number of crashes related to primary mechanical failure. When human error is cited as a major contributor in an air crash, this occurs most often in the form of failures in teamwork, in such areas as communication and shared mental models. 8 Historically, however, professional training has focused on technical, rather than on interpersonal, skills. Aviation has mandated that the flight and cabin