MacHELP: decision support on the Macintosh.

The paper describes an implementation of the HELP decision-support system for the Macintosh personal computer. Following a brief background description of HELP as it in implemented on a mainframe (TANDEM) computer, the principle features of the Macintosh version will be described. These include: the data-driven feature (an observation or decision may evoke another hypothesis or frame to be executed), the nesting feature by which a knowledge frame calls another frame whose output is needed to complete execution of the first), the ASK driver (the method by which the expert can direct the data requests when he creates a frame), the Query driver (a method by which the "program" determines the set of data items to asked) inheritance of properties among items in the data hierarchy, and Decision-driven Data Acquisition (DDA). The HELP decision-support system is the expert system portion of a large Hospital Information System in wide sue at several hospitals. It consists of knowledge frames that are disease or decision specific created by experts in various medical specialties, and are evoked automatically when data stored in a patient's record. The reason for implementing the expert system component of HELP on the Macintosh is to make it available as a stand-alone, easily portable system that will allow it to be used in a variety of different settings, for both educational and clinical decision support. Significant enhancements have been make to the Macintosh version which should increase the range of settings in which HELP can provide decision support.