PROBABILITY JUDGMENT IN MEDICINE - DISCOUNTING UNSPECIFIED POSSIBILITIES

Research in cognitive psychology has indicated that alternative descri ptions of the same event can give rise to different probability judgme nts. This observation has led to the development of a descriptive acco unt, called support theory, which assumes that the judged probability of an explicit description of an event (that lists specific possibilit ies) generally exceeds the judged probability of an implicit descripti on of the same event (that does not mention specific possibilities). T o investigate this assumption in medical judgment, the authors present ed physicians with brief clinical scenarios describing individual pati ents and elicited diagnostic and prognostic probability judgments. The results showed that the physicians tended to discount unspecified pos sibilities, as predicted by support theory. The authors suggest that a n awareness of the discrepancy between intuitive judgments and the law s of chance may provide opportunities for improving medical decision m aking.