You Get Who You Pay for: The Impact of Incentives on Participation Bias.

Designing effective incentives is a challenge across many social computing contexts, from attracting crowdworkers to sustaining online contributions. However, one aspect of incentivizing that has been understudied is its impact on participation bias, as different incentives may attract different subsets of the population to participate. In this paper, we present two empirical studies in the crowdworking context that show that the incentive offered influence who participates in the task. Using the Basic Human Values, we found that a lottery reward attracted participants who held stronger openness-to-change values while a charity reward attracted those with stronger self-transcendence orientation. Further, we found that participation self-selection resulted in differences in the task outcomes. Through attracting more self-directed individuals, the lottery reward resulted in more ideas generated in a brainstorming task. Design implications include utilizing rewards to target desired participants and using diverse incentives to improve participation diversity.