Abstract: "Dynamics of Open Source Movements"
This paper considers a dynamic model of the evolution of open source software projects, focusing on the evolution of quality, contributing programmers, and users who contribute customer support to other users. Our model has a public good problem that is partially mitigated by altruism. Programmers who have used features from open source software in the past are motivated to publish their own improvements, and the anticipation of these altruistic feelings may even lead them to choose to use open source rather than a commercial alternative that provides higher direct value. We consider two variants of the model, one in which programmer altruism is derived from the instrinsic quality improvement of the code, the other in which programmer altruism is related to the bene.ts end users derive from using the new code. In our model, end users require customer support to adopt open source, and this is provided by other users who received support themselves in the past. We show that to avoid a zero-quality steady state, projects require an initial critical mass of features and individuals willing to provide customer service. We derive additional comparative statics on the dynamics of this system. Finally, we analyze competition by commercial .rms with OSS projects, showing that for many (but not all) parameter values, far-sighted commercial .rms reduce their prices in order to slow the growth of OSS projects or even cause OSS projects to change trajectories towards the zero-quality steady-state.