Common Practice: Spillovers from Medicare on Private Health Care
研究发现，美国医疗保险（Medicare）通过随机信件干预减少抗精神病药物过度使用，不仅影响了其自身患者，还显著降低了私人保险患者的处方量，表明不同保险公司的支付方式存在溢出效应。
Efforts to raise US health-care productivity have proceeded slowly, potentially due to the fragmentation of payment across insurers. Each insurer’s efforts to improve care could influence how doctors practice for other insurers, leading to unvalued externalities. We study a randomized letter intervention by Medicare to curtail overuse of antipsychotics. The letters did not mention private insurance but reduced prescribing to these patients by 12 percent, much like the 17 percent effect in Medicare. We cannot reject onefor-one spillovers, suggesting that physicians use similar medical practice styles across insurers. Our findings establish that insurers can affect health care well outside their direct purview.