  We report on a large-scale empirical study investigating the relevance of
socio-technical congruence over key basic software quality metrics, namely,
bugs and churn. In particular, we explore whether alignment or misalignment of
social communication structures and technical dependencies in large software
projects influences software quality. To this end, we have defined a
quantitative and operational notion of socio-technical congruence, which we
call socio-technical motif congruence (STMC). STMC is a measure of the degree
to which developers working on the same file or on two related files, need to
communicate. As socio-technical congruence is a complex and multi-faceted
phenomenon, the interpretability of the results is one of our main concerns, so
we have employed a careful mixed-methods statistical analysis. In particular,
we provide analyses with similar techniques as employed by seminal work in the
field to ensure comparability of our results with the existing body of work.
The major result of our study, based on an analysis of 25 large open-source
projects, is that STMC is not related to project quality measures -- software
bugs and churn -- in any temporal scenario. That is, we find no statistical
relationship between the alignment of developer tasks and developer
communications on the one hand, and project outcomes on the other hand. We
conclude that, wherefore congruence does matter as literature shows, then its
measurable effect lies elsewhere.
