The Formation of Composite Hypotheses in Diagnostic Problem Solving: An Exercise in Synthetic Reasoning

The INTERNIST system, which is a computerbased diagnostic problem solver having Internal Medicine as i t s domain of discourse, employs a novel attention focusing heurist ic in order to deal sequentially with the component parts of a complex c l in ica l problem. The strategy of sequential problem formation and solution has proved to be effect ive in sorting out the complexi t ies and rendering a correct diagnosis in the great majority of c l in ica l cases tested. Experience with the system suggests, however, that many aspects of the search process could be s ign i f icant ly enhanced if it were possible to attend to the various component problems and their interrelationships simultaneously. Recent work on a successor system has been directed towards the development of strategies for the synthesis and analysis of composite hypotheses, which may be expected to yield more rapid convergence to the correct conclusion in many cases, and in at least some cases to prevent missed diagnoses.