REUSABILITY IN SOFTWARE MAINTENANCE - A JAPAN-USA COMPARISON

Japan benefits from a level of software reuse in software maintenance more than ten times the level in the USA. We report in this paper on our investigation during 1992 and 1993 into the management factors associated with that difference. The four main parts of this paper are the motivation for applying software reusability, maintenance management in the USA, maintenance management in Japan, and USA versus Japan. Our investigation included on-site visits in Japan and the USA, interviews with experts in Japan and the USA, and a review of the relevant Japanese and American literature (one of us speaks and reads Japanese fluently). Organizations in Japan applying software reuse report reduced maintenance backlogs, better satisfaction of customer (user) requests, and improved maintenance productivity. In Japan, about a third of organizations apply software reuse, and the reuse level typically is in the 50% to 75% range, we observe. In the USA, less than 2% of organizations apply software reuse in software maintenance, and the reuse level those organizations achieve typically is below 35%. The approach to software reuse in Japan is more business-oriented, with an emphasis on team work-methods and quality improvement. The approach in the USA is more technically oriented, with an emphasis on tools and operating practices. The approach in Japan reflects a tradition of building and maintaining in terms of assemblies and subassemblies to help control product quality over a long term. The approach in the USA reflects managements' pressure for a short-term payoff, and the relatively easy availability of personnel skills when needed. In both Japan and the USA, personnel factors are a major concern for information systems management in determining the extent of software reuse in software maintenance. Underlying all software maintenance reuse differences between Japan and the USA are structural and cultural differences which shape the extent and manner of applying software reusability in software maintenance.