In this paper, we investigate collective action in open source software development, where both volunteers and paid professionals essentially produce a public good. By using a large dataset, our logistic regression shows that adding more programming staff to the software projects increases their probability of success. This finding contradicts some dominant theories on software development as well as on the provision of public goods. As governments worldwide increasingly rely on open source software, our analysis has concrete implications for the public sector in contributing to the success of these projects.