How Artifact-Based and Authority-Based Coordination Affect Propagation Costs in Open Source Software Development

The success of open source software (OSS) projects depends on their ability to produce software architectures with low propagation costs, as such architectures demand little effort from developers. This study focuses on the project’s form of coordination—the way in which interdependent contributions are managed—as a driving force behind propagation costs. It distinguishes between two coordination archetypes. First, artifact-based coordination is found in egalitarian projects, in which developers only use the work artifact (the architecture itself), without direct interaction, to coordinate. Second, authority-based coordination is used in hierarchical projects (e.g., Linux Kernel) or when companies pay developers for their work. Using a computational model, this study compares these two coordination mechanisms by simulating how they build software architectures (formalized as design structure matrices) from interdependent contributions. As a contextual condition, the model considers the degree of architecture visibility, which is the developers’ (in)ability to see recent additions to the architecture. The model provides two insights. First, artifact-based coordination, as compared to authority-based coordination, generally leads to lower propagation costs. Second, decreasing the degree of architecture visibility reduces propagation costs, an effect that I describe as focal-layered superposition. These insights contribute to the literatures on coordination in OSS development and the mirroring hypothesis. They also have practical implications for the creation of preferable architectures in OSS development.