EMOS/1: An Evolution Metrics Model for Open Source Software

Open Source Software (OSS) has become the subject of much commercial and academic interest of last. 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 not suitable for measuring OSS evolution. In this paper, we designed a preliminary evolution metrics model named EMOS/1 which contains a set of new metrics defined for evaluating OSS specially. The most significant novelty of this model is that it takes some 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 EMOS/1. We find out the Open Source Community and its members also play essential role in OSS evolution. We expect our model can bring better understandings and explanations of phenomena in open source development and evolution.