The Determinants of Open Source Quality: An Empirical Investigation

Open source (OS) licenses differ in the conditions under which licensors and OS contributors are allowed to modify and redistribute the source code. While recent research has explored the determinants of license choice, we know little about the impact of license choice on project success. In this paper, we measure success by the speed with which programming bugs are fixed. Using data obtained from SourceForge.net, a free service that hosts OS projects, we test whether the license chosen by project leaders influences bug resolution rates. In initial regressions, we find a strong correlation between the hazard of bug resolution and the use of highly restrictive licenses. However, license choices are likely to be endogenous. We instrument license choice using (i) the human language in which contributors operate and (ii) the license choice of the project leaders for a previous project. We then find weak evidence that restrictive licenses adversely affect project success.