Quantitative analysis on medical service demand / supply behavior under the reform of the Japanese medical insurance system

在本研究中，我们开发了一个根据制度变化(如医疗保险制度中的共同支付方案修订)来估计政策效果的框架，并将其应用于实际数据。共付率的变化(即医疗服务价格的变化)对医疗服务需求/供给的影响是定量确认的；实验室检测和/或诊断成像的数量(这些对于治疗是必要的，但不能直接改善患者的健康状况)是价格敏感的。此外，我们还研究了反事实治疗效果估计的统计性质，特别是使用切换回归模型。对引入拍卖制度等促进竞争政策的效果进行了实证检验。

In the present study, we developed a framework for estimating the policy effects according to system changes such as the copayment scheme revision in the medical insurance system, and applied it to real data. The impacts of the change in the copayment rate (i.e. medical service price change) on the medical service demand/supply are quantitatively confirmed; the quantities of laboratory test and/or diagnostic imaging (these are necessary for treatments, but do not directly improve the health states of patients) are price-sensitive. Moreover, we investigate the statistical properties of the counterfactual treatment effect estimation, especially using the switching regression model. The effects of the competition promoting policy such as introducing the auction system are empirically examined.