Motivation: Open-source projects are often supported by companies, but such involvement often affects the robust contributor inflow needed to sustain the project and sometimes prompts key contributors to leave. To capture user innovation and to maintain quality of software and productivity of teams, these projects need to attract and retain contributors. Aim: We want to understand and quantify how inflow and retention are shaped by policies and actions of companies in three application server projects. Method: We identified three hybrid projects implementing the same JavaEE specification and used published literature, online materials, and interviews to quantify actions and policies companies used to get involved. We collected project repository data, analyzed affiliation history of project participants, and used generalized linear models and survival analysis to measure contributor inflow and retention. Results: We identified coherent groups of policies and actions undertaken by sponsoring companies as three models of community involvement and quantified tradeoffs between the inflow and retention each model provides. We found that full control mechanisms and high intensity of commercial involvement were associated with a decrease of external inflow and with improved retention. However, a shared control mechanism was associated with increased external inflow contemporaneously with the increase of commercial involvement. Implications: Inspired by a natural experiment, our methods enabled us to quantify aspects of the balance between community and private interests in open- source software projects and provide clear implications for the structure of future open-source communities.

A novel N-doped magnetic covalent organic framework (N-Mag-COF) has been synthesized.

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