Motivating the Unmotivated? Testing Conditional Lottery Incentives in an Ongoing Panel Survey

This study examines whether conditional lottery incentives, where the probability of winning increases with continued participation, can motivate panelists to reengage in a randomly sampled, quarterly online survey. Respondents were randomly assigned to one of three groups: a control group (CG) receiving the standard €10 incentive, treatment group 1 (T1) with an additional lottery offering ten Amazon vouchers worth €500, and treatment group 2 (T2) introducing conditionality by linking the probability of winning to participation in successive waves. This design tests whether reengagement depends not only on incentive size but also on respondents’ perceived ability to influence their odds of winning. Results show no statistically significant treatment effects. Neither the high-value lottery nor its conditional variant increased participation. Subgroup analyses reveal no systematic differences across prior participation, education, income, or country of origin. These findings confirm earlier evidence on the limited effectiveness of lotteries in survey research but extend it by testing conditionality as a motivational mechanism. Although conditional incentives strengthen the conceptual link between effort and reward, restoring agency alone appears insufficient to overcome deeper motivational barriers in quarterly online panels.