Presented is an analysis of think-aloud protocols of graduate students solving several different tasks in organic chemistry. The systems used by these subjects were classified. It was reported that the methodological system was most often used. (CW)

A broad range of well-structured problems--embracing forms of diagnosis, catalog selection, and skeletal planning--are solved in expert computer systems by the method of heuristic classification. These programs have a characteristic inference structure that systematically relates data to a pre-enumerated set of solutions by abstraction, heuristic…