[Rational choice, prediction, and medical decision. Contribution of severity scores]

The aim of this study was to determine what type of representation the medical doctor adopted concerning the uncertainty about the future in critically ill patients in the context of preoperative evaluation and intensive care medicine and to explore through the representation of the patient health status the different possibilities of choice he was able to make. The role played by the severity classification systems in the process of medical decision-making under probabilistic uncertainty was assessed according to the theories of rational behaviour. In this context, a medical rationality needed to be discovered, going beyond the instrumental status of the objective and/or subjective constructions of rational choice theories and reaching a dimension where means and expected ends could be included.