How does PSM apply to maintenance?
If the maintenance (or sustaining support) process is organized into periodic releases, PSM is implemented similar to a new systems development process. Issues are decided during the planning of the release and are based on things like schedule and staffing constraints, requirements/change request volume, etc. If the maintenance process treats every change request as ad hoc or continuous releases, issues and measures focus more on maintaining and improving baselines over time, versus monitoring discreet events. For instance, improvement goals may focus on reducing the backlog of change requests over time, responding more quickly to customer requests, improving software reliability, and maintaining or improving software maintainability. Finally, the issues and measures selected during a maintenance project will probably be different than those selected during the program’s development.
