A Method for Assessing Class Change Proneness

Change proneness is a quality characteristic of software artifacts that represents their probability to change in the future due to: (a) evolving requirements, (b) bug fixing, or (c) ripple effects. In the literature, change proneness has been associated with many negative consequences along software evolution. For example, artifacts that are change-prone tend to produce more defects, and accumulate more technical debt. Therefore, identifying and monitoring modules of the system that are change-prone is of paramount importance. Assessing change proneness requires information from two sources: (a) the history of changes in the artifact as a proxy of how frequently the artifact itself is changing, and (b) the source code structure that affects the probability of a change being propagated among artifacts. In this paper, we propose a method for assessing the change proneness of classes based on the two aforementioned information sources. To validate the proposed approach, we performed a case study on five open-source projects. Specifically, we compared the accuracy of the proposed approach to the use of other software metrics and change history to assess change proneness, based on the 1061-1998 IEEE Standard on Software Measurement. The results of the case study suggest that the proposed method is the most accurate and reliable assessor of change proneness. The high accuracy of the method suggests that the method and accompanying tool can effectively aid practitioners during software maintenance and evolution.