Sources of Geographic Variation in Health Care: Evidence From PatientMigration*
利用医疗保险患者迁移数据，分离需求和供给因素，发现美国医疗保健利用的地理差异中40-50%由需求侧因素（健康与偏好）解释，其余由地方供给因素解释。
Abstract We study the drivers of geographic variation in U.S. health care utilization, using an empirical strategy that exploits migration of Medicare patients to separate the role of demand and supply factors. Our approach allows us to account for demand differences driven by both observable and unobservable patient characteristics. Within our sample of over-65 Medicare beneficiaries, we find that 40–50% of geographic variation in utilization is attributable to demand-side factors, including health and preferences, with the remainder due to place-specific supply factors.