STUDYING THE USE OF EXTRINSIC INCENTIVES TO SUPPORT CROWDSOURCED SOFTWARE ENGINEERING ACTIVITIES
Extrinsic incentives help attract participants to Crowdsourced Software Engineering (SE) activities (e.g., open source development and Stack Overﬂow contributions). There are two types of extrinsic incentives: 1) monetary incentives such as ﬁnancial rewards (e.g., vulnerability bounties) or ﬁnancial supports (e.g., monetary donations). 2) Non-monetary incentives such as badges which are a form of recognition. Prior work noted the importance of extrinsic incentives to support different forms of Crowdsourced SE activities. In this Ph.D. thesis, we study the use of extrinsic incentives to support Crowdsourced SE activities. In particular, we focus on two of the most successful and popular examples of Crowdsourced SE activities: open source development and Stack Overﬂow contributions (e.g., answering questions). We examine the use of monetary extrinsic incentives for addressing issues in and operating open source projects, and the use of non-monetary extrinsic incentives by online technical Q&A websites. More speciﬁcally, for monetary extrinsic incentives, we examined issues with monetary bounties for addressing them, then we studied the association between such “issue bounties” and the addressing likelihood of their associated issues across several open source projects. We also studied the use of monetary donations for supporting the operation of open source projects on GitHub by looking at how such donations are used to cover expenses across several projects. Project maintainers can leverage our study to better address issues and manage the budgets of their open source projects. For non-monetary extrinsic incentives, we investigated the association between reputation bounties and Stack Overﬂow questions in terms of the solving-likelihood, solving-time, and trafﬁc, respectively. We observed that while reputation bounties are not a silver bullet for getting a question solved faster, they are associated with a higher solving-likelihood of a question in most cases. Our empirical studies highlight the importance of extrinsic incentives in supporting Crowdsourced SE activities.