  In this research, we investigate peer review in the development of Linux by
drawing on network theory and network analysis. We frame an analytical model
which integrates the sociological principle of homophily (i.e., the relational
tendency of individuals to establish relationships with similar others) with
prior research on peer-review in general and open-source software in
particular. We found a relatively strong homophily tendency for maintainers to
review other maintainers, but a comparable tendency is surprisingly absent
regarding developers' organizational affiliation. Such results mirror the
documented norms, beliefs, values, processes, policies, and social hierarchies
that characterize the Linux kernel development. Our results underline the power
of generative mechanisms from network theory to explain the evolution of peer
review networks. Regarding practitioners' concern over the Linux
commercialization trend, no relational bias in peer review was found albeit the
increasing involvement of firms.
