Connections between Incentive Behavior and User Engagement: Evidence from Stack Overflow

To motivate user contributions, websites that feature user-generated content often implement incentive hierarchies. Badges are awarded to users for behaviors such as completing a certain number of actions of a specific type. Yet the existing empirical literature remains largely unclear whether and how badges can influence and steer user behavior. This paper examines the impact of badges on user activities in an online Q&A community, namely StackOverflow.com. By characterizing distinct patterns of change in user effort, we evaluate how users in different trajectory groups respond to badges. Our findings show that the group-based trajectory model can identify five distinct behavior patterns and badges play a significant role in specific groups. Furthermore, we find that the steering effect varies for badges of different classes and categories. From a dynamic perspective, we argue that incentivizing behavior does not work for everyone but can be an important predictor of user engagement behavior trajectories