The Development Process of the Medical Decision Making, by VIMLA L. PATEL, Centre for Medical Education, McGill University. The superior performance of expert physicians has been shown to reside not in the amount of information they possess, but in the organization of knowledge in memory. A process of knowledge acquisition, which is characterized by a U-shaped performance curve, where the vertical and horizontal axes are level of performance and level of expertise, respectively, achieves this. This challenges the usual assumption in medical education that the process of knowledge acquisition for decision making increases linearly as a function of expertise. Research into decision-making strategies of expert physicians has shown that they use data-driven heuristics when solving routine problems. The development of this strategy is a function of sophisticated knowledge structures and is implicitly acquired during training. Physicians use hypothesis-driven strategies when confron ted with complex and uncertain cases. Both these strategies are error-prone, but the nature of errors is different. In the former case errors are very serious, if the knowledge is inadequate. In the later case, the errors can be corrected, but it requires time and thus hinders efficient decision making.