Probability Judgment in Medicine

Abstract

Research in cognitive psychology has indicated that alternative descriptions of the same event can give rise to different probability judgments. This observation has led to the de velopment of a descriptive account, called support theory, which assumes that the judged probability of an explicit description of an event (that lists specific possibilities) generally exceeds the judged probability of an implicit description of the same event (that does not mention specific possibilities). To investigate this assumption in medical judgment, the au thors presented physicians with brief clinical scenarios describing individual patients and elicited diagnostic and prognostic probability judgments. The results showed that the phy sicians tended to discount unspecified possibilities, as predicted by support theory. The authors suggest that an awareness of the discrepancy between intuitive judgments and the laws of chance may provide opportunities for improving medical decision making. Key words: probability judgment; support theory; unpacking principle; cognition. (Med Decis Making 1995;15:227-230)

Get full access to this article

View all access options for this article.

References

Pauker SG , Kopelman RI How sure is sure enough? N Engl J Med. 1992 ;326:688-91.

Kahneman D , Slovic P , Tversky A (eds). Judgment under Uncertainty: Heuristics and Biases. New York: Cambridge University Press, 1982.

von Winterfeldt D. , Edwards W. Decision Analysis and Behavioral Research. New York: Cambridge University Press, 1986.

Fischhoff B. , Slovic P. , Lichtenstein S. Fault trees: sensitivity of estimated failure probabilities to problem representation . J Exp Psychol Hum Percept Perform. 1978;3:552-64.

Tversky A. , Koehler DJ Support theory: a nonextensional representation of subjective probability . Psychol Rev. 1994;101:547-67.

Goldberg RJ , Gore JM , Alpert JS , et al. Cardiogenic shock after acute myocardial infarction: incidence and mortality from a community-wide perspective 1975 to 1988. N Engl J Med. 1991;325:1117-22.

Hourihane J. CT scans and the common cold. N Engl J Med. 1994;1330:1826-7.