Characteristics of Unmaintainable Source Code in Software Development by Multiple Organizations

In software development, there are numerous reasons why a development organization changes. These include cost reduction and retiring developers. Often the quality of software developed by multiple organizations is low, leading to problems such as difficulty in the evolution of source code. To detect factors indicating low evolvability of software, we focus two maintain-ability characteristics of software development: defect proneness and refactoring tendencies of the source code. We investigate the changes in the relationship of software metrics and the number of defects. Then we compare the results and editing tendencies for refactoring and evolving software in experiments using OpenOffice.org, which is developed by multiple companies, and a tool developed by outsourcing. Defects tend to concentrate on files that depend on many other files. Additionally, the code review confirms that refactoring before and after a development organization change is important for future developments.