There have been growing concerns that general practitioner (GP) services in England, which are based on registration with a single practice located near the patient's home, are not sufficiently convenient for patients. To inform the decision as to whether to change registration rules allowing...

We study the power of social incentives to increase individuals' investment in preventive health using small financial incentives with group conditionality. In a field experiment in El Salvador, we compare those to equivalent individual incentives. Despite the uncertainty about others' behavior,...