Designing cost-effective scalable behavioral interventions

Abstract

This dissertation brings together five essays in behavioral and experimental economics. The first three focus on topics in health economics with implications for labor economics, while the final two examine virtual volunteering and its effects on digital participation in later life. Chapter 1 derives the relevance and the connectedness of these topics for social services and the society as a whole. Chapter 2 is a systematic review and meta-analysis on the effects of monetary incentives and goal-setting in physical activity interventions. Results show that incentives raise attendance and steps, but their effectiveness depends critically on the design of reference groups. When both treatment and reference groups receive structured goals, the performance-enhancing effect of monetary incentives diminishes, underscoring the importance of careful study design. Chapter 3 reports a field experiment testing the behavioral effects of different goals under constant financial incentives. High-threshold goals resulted in significant and costefficient increases in daily steps, particularly among low performers, whereas open-ended instructions proved more effective for high performers. These findings highlight that aligning goal difficulty with baseline ability is a key condition. Chapter 4 examines team-based incentives in a field experiment. Assigning participants to two-person teams revealed that team incentives, where either the low performing or top performing team member is payoff relevant, substantially improved performance of low performers. However, capping the incentive at 10,000 steps constrained potential gains for top performers. The results demonstrate both the potential and the limits of peer-based motivational structures in health interventions. Chapter 5 evaluates two common behavioral interventions to foster volunteer engagement, Gift-Exchange and the Foot-in-the-Door technique. Contrary to expectations, neither strategy outperformed the control group. Responsiveness was concentrated among individuals who rated the project highly, indicating that mission appeal is more decisive than monetary incentives. Chapter 6 investigates an intergenerational, location-independent mentoring program designed to reduce the second-level digital divide among older adults. The analysis shows that the intervention significantly improved digital competence, reduced technology anxiety, and strengthened self-efficacy. Curricular service-learning modules enhanced competence, whereas voluntary tandems were more effective in reducing anxiety.