A Motivation-Hygiene Model of Open Source Software Code Contribution and Growth

The success of open source software (OSS) projects depends on sustained contributions by developers who often display a wide variety of contribution patterns. Project leaders and stakeholders would strongly prefer that developers not only maintain but preferably increase their contributions over time as they gain experience. Corporations increasingly complement OSS developer motivations (such as fit in terms of shared values with the project community) by paying them to sustain contributions. However, practitioners argue whether payment helps or hurts projects because monetary compensation may dampen developer motivation in the long run, making it difficult for project leaders to understand what to expect from developers over time. Using Herzberg motivation-hygiene framework, we explore how developer perceptions of value fit with the project and being paid interact to determine the level of code contribution and its rate of change over time (i.e., growth). Using a survey of 564 developers across 431 projects on GitHub, we build a three-level growth model explaining the code contribution and its growth over a six-month period. We find that value fit with the project positively influences both the level and growth of code contribution. However, there are notable differences among paid and unpaid developers in the impact of value fit on their level and growth in code contributions over time. The implications of our work will be of interest to researchers, practitioners, and organizations investing in open source projects.