The Diagnostic Process with Special Reference to Errors

Abstract

An analysis is made of the losses due to errors in the diagnostic process. The basic assumption is that the doctor should try to maximize expected utility, where the utility allows both for the health of the patient and for »costs« of various kinds. This assumption leads to the view that in general the doctor should make use of a diagnostic search tree. Owing to the difficulty of estimating utilities and of back-tracking in a large tree it is convenient for him to use substitutes for utility, called quasi-utilities, such as mean information transfer or expected weight of evidence. After listing a number of such quasi-utilities, the effect on their expectations due to error is considered. The losses can be larger than might have been supposed. Much of the analysis could also be applied to scientific problems other than to medical diagnosis.