Assessing Software System Maintainability using Structural Measures and Expert Assessments

Software maintenance is often expensive; hence, strategies for assessing the maintainability of complete software systems are important. Nevertheless, a software client usually has few means of assessing the maintainability of a software system as part of the acquisition process. Assessing the maintainability of complete systems is difficult due to the influence of many factors, such as the people, tasks and tools, in addition to the code. Furthermore, most research on maintainability focuses on individual classes of individual systems. This paper describes an empirical study in which the maintainability of four functionally equivalent systems developed in Java was assessed using both structural measures and expert assessments. The results suggest that such a combination may be useful. Although the assessment based on structural measures mostly corresponded with the expert assessments, there were several examples of potential problems regarding maintainability that were not captured by the structural measures.