FIRST AID: a design philosophy and a program for on-line symptom processing.

A major problem for computer-aided diagnosis systems, particularly those designed for on-line use in clinical settings, is that their operation may be obtrusive or unacceptable within established clinical routine. Criteria for a general approach to the design of the on-line aids in clinical decision-making are presented. An interpreter is described that is designed to be broadly applicable within the area of statistical diagnosis, but which is also designed to encourage the development of congenial clinical systems. The use of the program and its features are illustrated by an application in the diagnosis of 'dyspepsia'.