On the Meaning of Quantified Maintainability

Maintainability analysis stands today where reliability was ten years ago. Many and varying definitions of maintainability have been proposed; many mathematical approaches to maintainability and its various aspects have been pursued. Nevertheless, there is presently no general agreement on the definition of maintainability or on the technique of its quantification. In addition, there is insufficient meaningful maintainability field and laboratory data. As in the case of reliability, analytical techniques are only a part of the maintainability improvement effort. There is a need for improvement in both the design of the total maintenance system as well as analytical techniques for its evaluation.