dispositional characteristics appear to impact peoples' decision making when faced with situations characterised by uncertainty, a characterization of an unknown future outcome, and ambiguity, a characterisation of the present situation where multiple possibilities exist. there is a paucity of decision making research of an applied nature which limits the application of theory to practice. this study investigated the role of dispositional reactions to uncertainty in decision making in an applied medical setting by integrating theory and research findings from traditional economics and emerging cognitive and personality psychology models. we examined the relationship and predictive power of emergency physicians' affective and dispositional reactions to uncertainty and propensity for risk taking in clinical situations when deciding to admit a patient or release them home. patients who present in the emergency department do so with a range of medical complaints, each with a different degree of risk and ambiguity. these properties of the patient/physician encounter were hypothesized to impact individual physicians differently, depending on the physician's trait and state reactions to uncertainty and propensity for risk taking. specifically, it was hypothesized that emergency physicians' admission and discharge decisions and length of time required to arrive at a decision would be impacted by the physician's unique personality features and the degree of ambiguity and risk inherent in the patient's condition. emergency physicians' dispositional characteristics were not found to playa significant role in the decision to admit patients. limitations and directions for future research are discussed.