Incentives and Habit Formation in Health Screenings: Evidence from the Illinois Workplace Wellness Study

We study habit formation in annual biometric health screenings using a field experiment that randomly assigned financial incentives to 4,799 employees over three years. Completing the first screening raised subsequent screenings by 32.4-36.0 percentage points (84%-90%) annually. Habit formation was similar whether employees were offered screenings as part of a comprehensive wellness program or just screenings alone, suggesting such habits can develop without frequent interactions. We rule out inattention as an explanation, using a subsample assigned more salient incentives. The long-run effect stems from the initial decision to participate, indicating a habit formation process with a one-shot mechanism.