Personalizing policies can theoretically increase their effectiveness. However, personalization is difficult when individual types are unobservable and the preferences of policymakers and individuals are not aligned, which could cause individuals to misreport their type. Mechanism design offers a strategy to overcome this issue: offer a menu of policy choices, and make it incentive-compatible for participants to choose the "right" variant. Using a field experiment that personalized incentives for exercise among 6,800 adults with diabetes and hypertension in urban India, we show that personalizing with an incentive-compatible choice menu substantially improves program performance, increasing the treatment effect of incentives on exercise by 80% without increasing program costs relative to a one-size-fits-all benchmark. Personalizing with mechanism design also performs well relative to another potential strategy for personalization: assigning policy variants based on observables. |
