Insurance coverage and agency problems in doctor prescriptions: Evidence from a field experiment in China

This study examines doctors' prescribing decisions using controlled hospital visits with randomized patient insurance and doctor incentive status. The results suggest that, when they expect to obtain a proportion of patients' drug expenditures, doctors write 43% more expensive prescriptions to insured patients than to uninsured patients. These differences are largely explained by an agency hypothesis that doctors act out of self-interest by prescribing unnecessary or excessively expensive drugs to insured patients, rather than by a considerate doctor hypothesis that doctors take account of the tradeoff between drug efficacy and patients' ability to pay.