Report Number: CS-TR-83-996
Institution: Stanford University, Department of Computer Science
Title: Strategic explanations for a diagnostic consultation system
Author: Hasling, Diane Warner
Author: Clancey, William J.
Author: Rennels, Glenn
Date: November 1983
Abstract: This paper examines the problem of automatic explanation of reasoning, especially as it relates to expert systems. By explanation we mean the ability of a program to discuss what it is doing in some understandable way. We first present a general framework in which to view explanation and review some of the research done in this area. We then focus on the explanation system for NEOMYCIN, a medical consultation program. A consultation program interactively helps a user to solve a problem. Our goal is to have NEOMYCIN explain its problem-solving strategies. An explanation of strategy describes the plan the program is using to reach a solution. Such an explanation is usually concrete, referring to aspects of the current problem situation. Abstract explanations articulate a general principle, which can be applied in different situations; such explanations are useful in teaching and in explaining by analogy. We describe the aspects of NEOMYCIN that make abstract strategic explanations possible--the representation of strategic knowledge explicitly and separately from domain knowledge--and demonstrate how this representation can be used to generate explanations.