Expert System Verification and Validation Part II: Implementing the Concepts

Verification and validation (V&V) have been defended as necessary and sufficient elements of the process for evaluating the expert system. An expert system is viewed as “verified” to the extent that its output statements describing the system are confirmed to a reasonable degree of strength. It is viewed as “validated” to the extent that it produces situationally relevant, correct answers at the location where it is installed. A gypsum wallboard expert system is evaluated in terms of these definitions. During the system’s development, its elements and inferencing processes were verified through a process of having facility personnel confirm the system’s elements and inferencing. On installation, the system was validated through an experiment that provided the basis for a statistical comparison of diagnoses by personnel and the system. The V&V procedure is offered as a means to improve the acceptability of expert systems to facilities where the system is to be installed.