Cost benefit analysis and the art of software maintenance

As software maintenance requirements continue to grow, conflicting with demands for new development, managers must continually evaluate the cost effectiveness of various maintenance strategies. He shows that one can measure and use a significant benefit from maintenance-the reduction in failure risk-to evaluate maintenance strategies. The ability to measure the differential risk of failure in modules within a system can be used to design high-risk-first maintenance strategies and to motivate the effort. Moreover, maintenance's impact on failure risk can demonstrate whether it is advantageous to fix errors as soon as they are found or perform scheduled maintenance in the future. Failure risk assessments can also be used to measure the effectiveness of perfective maintenance strategies. Not only can this type of maintenance be justified, but alternative strategies can be compared to determine which will minimize failure risk.<>