MAINTENANCE PERFORMANCE—A DECISION PROBLEM

SUMMARY The use of many published indices as aids for decision-making is demonstrated to be largely unsubstantiated in theory and of only limited value in practice. This paper attempts to define the useful areas of applications of indices in the decision-making process. A technique is postulated whereby indices are used as a measure of the state of the system, and a decision-rule, which is compatible with some real objective, is determined. In this way the value of an index can prescribe what action is necessary rather than just indicate that some action is necessary. The arguments are developed in the context of the maintenance function, but the general conclusionscan be applied equally well to other indices irrespective of their field of application.