Abstract

A rational justification for therapeutic decisions can be developed using probability and decision theory. The set of treatments and their outcomes or consequences, which are states of health, have to be defined; and estimates made of the probabilities of outcomes, their utilities, and the costs of treatments. Most difficult is the estimation of utilities of states of health but this may be possible using a wagering technique. Until it is possible to establish some equivalence between utility and money, costs may be introduced by measuring the efficiency of treatment by comparing expected utilities per unit cost. The whole method is examined practically in a plausible clinical setting. Emphasis is laid on the value of testing the completed model using a computer to get an intimate feel of the problem using different assumptions and different values for all the parameters.