Sponsorship Funding in Open-Source Software : Effort Reallocation and Spillover Effects in Knowledge-Sharing Ecosystems

This study investigates the effects of sponsorship-based funding on open-source software contributors within a knowledge-sharing ecosystem. Specifically, we examine the influence of sponsorship on contributors' activities on the host platform, where funding is received, as well as on a complementary platform without funding. While it is anticipated that sponsorship would increase the overall effort on the host platform, the reallocation of effort between different types of contribution activities (i.e., knowledge creation and maintenance) on the host platform, as well as its spillover effects on other complementary platforms, remain unclear. To address these questions, we analyze the impact of GitHub's sponsorship-funding feature introduced in 2019 on the contribution behavior of the contributors who are listed for the funding. Our methodology involves identifying contributors active on both the host platform (GitHub or GH) and the complementary platform (Stack Overflow or SO) and collecting contributor-level data from both platforms. Using a difference-in-differences estimation framework, we find that a contributor's sponsorship listing on GH leads to an effort reallocation between contribution activities on GH, specifically increasing maintenance-related activities (i.e., reviews of pull requests) while leaving knowledge creation (i.e., pull requests) unaffected. Furthermore, we find evidence of an effort distortion effect that leads to a negative spillover to their contributions on SO, and an effort mirroring effect where contributors listed for sponsorship shift their efforts toward knowledge-maintenance activities, akin to those seen in the host platforms. We discuss the significant implications of these findings