“Communication and Code Dependency Effects on Software Code Quality: An Empirical Analysis of Herbsleb Hypothesis”, Suvodeep Majumder, Joymallya Chakraborty, Amritanshu Agrawal, Tim Menzies2019-04-22 (end-to-end)⁠:

Prior literature has suggested that in many projects 80% or more of the contributions are made by a small called group of around 20% of the development team. Most prior studies deprecate a reliance on such a small inner group of “heroes”, arguing that it causes bottlenecks in development and communication. Despite this, such projects are very common in open source projects. So what exactly is the impact of “heroes” in code quality?

Herbsleb argues that if code is strongly connected yet their developers are not, then that code will be buggy. To test the Herbsleb hypothesis, we develop and apply two metrics of (a) “social-ness’” and (b) “hero-ness” that measure (a) how much one developer comments on the issues of another; and (b) how much one developer changes another developer’s code (and “heroes” are those that change the most code, all around the system). In a result endorsing the Herbsleb hypothesis, in over 1,000 open source projects, we find that “social-ness” is a statistically stronger indicate for code quality (number of bugs) than “hero-ness”.

Hence we say that debates over the merits of “hero-ness” is subtly misguided. Our results suggest that the real benefits of these so-called “heroes” is not so much the code they generate but the pattern of communication required when the interaction between a large community of programmers passes through a small group of centralized developers. To say that another way, to build better code, build better communication flows between core developers and the rest.

In order to allow other researchers to confirm/improve/refute our results, all our scripts and data are available, on-line at Github.