Architectural Stability Evolution in Open-Source Systems

Open-source software systems are becoming progressively vital these days. Since open-source softwares are usually developed in a different management style, the quality of their architectures needs to be studied. ISO/IEC SQuaRe quality standard characterized stability as one of the sub-characteristics of maintainability. Unstable software architecture could cause the software to require high maintenance cost and effort. Almost all stability related studies target the package level. To our knowledge, there has been no proposed work in literature that addresses the stability at the system architecture level. In this work, we propose a simple, yet efficient, technique that is based on carefully aggregating the package level stability in order to measure the change in the architecture level stability as the architecture evolution happens. The proposed method can be used to further study the cause behind the positive or negative architecture stability changes.