Aristotle vs. Ringelmann: A response to Scholtes et al. on Superlinear Production in Open Source Software

On December 19, 2015, Scholtes et al.'s work was published online in the Journal of Empirical Software Engineering, in which they challenged the exciting findings that we (with another co-author) presented in 2014, showing that open source software production exhibits superlinear productive bursts. We presented our findings as the first quantification of Aristotle's famous adage: The whole is more than the sum of its parts. In contrast, Scholtes et al. referred to Maximilien Ringelmann, a French agricultural engineer (1861-1931) who discovered the tendency for individual members of a group to become increasingly less productive as the size of their group increases. Since Ringelmann, the topic of collective intelligence has interested numbers of researchers in social sciences, as well as practitioners in management aiming at improving the performance of their team. And indeed, in most research and practice case studies, the Ringelmann effect has been found to hold. Our results challenge common wisdom, precisely because the Ringelmann effect has been replicated in countless experiments. We are glad that the study by Scholtes et al. allows us to explain further our findings by highlighting the methodological aspects that condition our diverging results. In particular, the definitions of group sizes and measurement periods are essential to explain the different conclusions. This healthy debate enriches the understanding on group productivity, in particular in the case of open source software production.