  Academic software development practices often differ from those of commercial
development settings, yet only limited research has been conducted on assessing
software development practises in academia. Here we present a case study of
software development practices in four open-source scientific codes over a
period of nine years, characterizing the evolution of their respective
development teams, their scientific productivity, and the adoption (or
discontinuation) of specific software engineering practises as the team size
changes. We show that the transient nature of the development team results in
the adoption of different development strategies. We relate measures of
publication output to accumulated numbers of developers and find that for the
projects considered the time-scale for returns on expended development effort
is approximately three years. We discuss the implications of our findings for
evaluating the performance of research software development, and in general any
computationally oriented scientific project.
