On the relationship between design discussions and design quality: a case study of Apache projects

Open design discussion is a primary mechanism through which open source projects debate, make and document design decisions. However, there are open questions regarding how design discussions are conducted and what effect they have on the design quality of projects. Recent work has begun to investigate design discussions, but has thus far focused on a single communication channel, whereas many projects use multiple channels. In this study, we examine 37 Apache projects and their design discussions, the project’s design quality evolution, and the relationship between design discussion and design quality. A mixed method empirical analysis (data mining and a survey of 130 developers) shows that: I) 89.51% of all design discussions occur in project mailing list, II) both core and non-core developers participate in design discussions, but core developers implement more design related changes (67.06%), and III) the correlation between design discussions and design quality is small. We conclude the paper with several observations that form the foundation for future research and development.