SOFTWARE COST REDUCTION METHODS IN PRACTICE - A POSTMORTEM ANALYSIS

Sixty percent of the software costs associated with the design, development, and implementation of computer systems occurs in the maintenance phase. Since change in intrinsic in software, a significant reduction in the maintenance costs can be realized by recognizing the evolutionary aspects of software and integrating a design for change philosophy into the engineering life-cycle. Programs must be designed to be alterable and the resulting change process rigorously planned and controlled. From 1984 to 1987, the government funded a large, computer-based training effort based on these goals. The training system software provided hands-on-training for a large collection/processing system by emulating the man-machine interfaces. The fundamental goal of the design and documentation effort was to minimize the impact of implementing expected system changes to the training system. Initial maintenance metrics collected during 1988 and 1989 for the effort suggest that several of the project design/documentation and maintenance goals were realized. The purpose of this paper is to revisit the design methodology and goals of the effort by analyzing change data gathered during the system test and early maintenance phases. This data strongly suggests that integrating a design for change philosophy into the software development practices has the potential to significantly reduce full life-cycle costs.