Magnet or sticky? an OSS project-by-project typology.

For Open Source Software (OSS) projects, retaining existing contributors and attracting new ones is a major concern. In this paper, we expand and adapt a pair of population migration metrics to analyze migration trends in a collection of open source projects. Namely, we study: (1) project stickiness, i.e., its tendency to retain existing contributors and (2) project magnetism, i.e., its tendency to attract new contributors. Using quadrant plots, we classify projects as attractive (highly magnetic and sticky), stagnant (highly sticky, weakly magnetic), fluctuating (highly magnetic, weakly sticky), or terminal (weakly magnetic and sticky). Through analysis of the MSR challenge dataset, we find that: (1) quadrant plots can effectively identify at-risk projects, (2) stickiness is often motivated by professional activity and (3) transitions among quadrants as a project ages often coincides with interesting events in the evolution history of a project.