A New Method for Discovering Rules from Examples in Expert Systems

Abstract The experts often cannot explain why they choose this or that decision in terms of formalized “if-then” rules; in these cases we have a set of examples of their real decisions, and it is necessary to reveal the rules from these examples. The existing methods of discovering rules from examples either demand that the set of examples be in some sense complete (and it is often not complete) or they are too complicated. We present a new algorithm which is always applicable. This algorithm is based on the formalization of rough set theory, a formalization which describes the case of incomplete information.