Honestly, I'd be surprised if the total number of studies on gender balance in open-source projects was higher than single digits. This is probably true, becau

Honestly, I'd be surprised if the total number of studies on gender balance in open-source projects was higher than single digits. This is probably true, because open-source development doesn't seem to be a well-studied phenomenon in social science; but the effects of diversity on group dynamics in general have been studied extensively. While you may disagree, I'm willing to make the provisional assumption that working and personal relationships among open-source developers are not substantially different from groups which are more commonly studied. (I currently don't have much in the way of academic access, but a few Google Scholar searches and reading some abstracts will at least reveal a large volume of research on these topics. i.e., http://scholar.google.com/scholar?q=group+diversity+positive+effects&btnG=&hl=en&as_sdt=1%2C5 http://scholar.google.com/scholar?q=group+diversity+positive...) More interesting, I think, is the idea that there must be some "real-world measure of goodness" (market share? lines of code?) which is improved by diversity, in order for pursuing diversity to be worthwhile. I'd be willing to argue that even if better diversity led to a persistent decrease in technical quality, it would be worthwhile in terms of positive external effects on society. While "low barriers to entry for all demographic groups" might not be an advantage to the group looking for developers, it could benefit society in the same ways as wheelchair ramps, good employee working conditions, regulation of animal medical testing, and other things we encourage in spite of their cost. In other words -- diversity and fairness can be valued for their own sake, just as much as code quality is a value. (I actually don't think increased diversity would have any negative effects on technical quality, in the long term: instead I'd expect a null effect or a slight positive. I wouldn't be surprised by a short-term negative blip as potentially-biased education and training learns to cope with different people, but I don't see that as a real barrier given the societal positives.) edit for grammar