Modularity and Inequality of Code Contribution in Open Source Software Development

We develop a model to study how the code architecture affects open source software (OSS) development. A major advantage brought by a modular architecture of code base is that it reduces both the cognitive cost and the coordination cost associated with OSS development. We show that in OSS development, the amount of individual code contribution, the inequality of code contribution among programmers, and the total output of code all have nonlinear relationships with the level of modularity of the project. We further empirically test the predictions using the Source Forge OSS development data, and the results confirm our theoretical predictions.