Measuring the evolution of open source software systems with their communities

Open Source Software (OSS) has become the subject of much commercial and academic interest in last few years. As traditional software, OSS also evolves to fulfill the need of stakeholders. Therefore, providing quantitative metrics for OSS evolution has also become an urgent issue. However, most existing studies of software evolution have been performed on systems developed within a single company using traditional management techniques. These metrics models are inadequate to measure OSS evolution. In this paper, we describe a preliminary evolution metrics set for evaluating OSS. The most significant novelty of this model is that it takes specific properties of Open Source Community (OSC) into consideration. In another word, we measure the evolution of OSS and OSC together. We also provide a lightweight case study on Ubuntu project using this metrics set. We find out that the Open Source Community and its members also play essential role in OSS evolution. We expect this metrics model can bring better understandings and explanations of phenomena in open source development and evolution.