A model for physicians' therapeutic decision making.

We explored physician's cognitive processes when making therapeutic decisions in a complex situation in which more than one treatment option is acceptable. Eighteen internists were presented with three hypothetical cases of patients with coronary artery disease and were asked to explain their treatment decisions. Based on process tracing, we characterized their method of therapeutic decision making. We found that physicians use a three-stage process that we call focal composite analysis: (1) selection of a few facts (focal points) and evaluation of each fact individually with respect to treatment options; (2) reassessment of the value of the focal points with respect to each other and unification of the case; and (3) summation of the values of the focal points to make the final decision. Using this model, we predicted physicians' actual treatment decisions in 96% of the hypothetical cases. Further analysis revealed a wide variety of focal points chosen overall, with most physicians choosing different focal points in each case. Of a total of 32 focal points chosen in three cases, only two focal points were predictors of the physicians' actual treatment choices. We conclude that in the complex problem considered here physicians use a staged process of choosing and evaluating information to make therapeutic choices.