The Theoretical and Experimental Study on Reform of Payment System for Reimbursement to Medical Institutions

医疗奖励DRG-PPS （dynagose相关集团和预期支付系统）已被引入美利坚合众国和其他国家，减少了国家医疗费用，特别是医院支付。日本当局还计划将DRG-PPS纳入现有的医疗奖励制度。然而，日本医疗保健市场的特点是医院之间的竞争最为激烈，因为患者可以自由选择和改变他们所去的任何医院。因此，要分析DRG-PPS引入日本医疗市场的影响，需要一个动态的框架，以使患者反复选择医院。在这个项目中，我们调查了1)DRG-PPS的引入是否降低了人均医疗服务水平，2)在引入后的一段时间内，医疗报销成本是否出现了回弹，以及3)什么样的医疗支付制度实现了最优的医疗供应。综上所述，第一，尽管各医院的代理系数不同，但各医院在稳定状态下的人均医疗服务水平是相同的。与按服务收费相比，DRG-PPS的引入降低了医疗保健的服务水平。其次，当我们研究趋向于均衡的动态路径时，我们可以发现医疗报销成本的回调。补偿成本的回荡意味着稳态的补偿成本比引入DRG-PPS后的补偿成本要大得多。这种现象的产生是由于一些医院极度尊重病人的利益，而不是医院的利益。最后，在一定条件下，存在一个复合支付系统，以最大限度地提高患者的净收益，即从患者接受医疗保健所获得的收益中扣除医疗成本。

DRG-PPS (Dynagoses Related Group and Prospective Payment System) for medical rewards has been introduced to the United States of America and other countries reducing national medical costs, especially hospital payments.The Japanese authority also plans to adapt DRG-PPS to the existing medical reward system. However, the Japanese market for health care is characterized by the most severe competition among hospitals since patients can freely choice and change any hospital that they visit.Therefore, to analyze effects concerning an introduction of DRG-PPS into the Japanese health market needs a dynamic framework possible to that patient choices hospital repeatedly.In this project, we investigate1) whether the introduction of DRG-PPS decreases a per capita service level of health care or not,2) whether any swingback of reimbursement cost for health care happened in the periods that follow it or not,and 3) what kind of medical payment system fulfills any optimal supply for health care.Summarizing the results, first, the per capita service level of health care supplied in steady state is the identical to every hospital, regardless of that each hospital has a different agent coefficient. Then the introduction of DRG-PPS happen to decrease the service level of health care relatively to under Fee-for-Service.Next, when we investigate dynamic paths to converge on equilibrium, we can find the swingback of reimbursement cost for health care. The swingback of reimbursement cost means that reimbursement cost in steady state becomes much larger than in the morrow of introducing DRG-PPS. This phenomenon arises when some hospitals extremely respect patient benefit rather than hospital profit.Finally, under certain condition, there is a composite payment system to maximize the net benefit for patient that deducts a medical cost from a patient benefit gained by receiving health care.