声誉能解决医疗保险的“双刃剑”难题吗？——来自实验的证据

医疗保险虽然有利于提高医疗卫生服务的可及性和公平性，但也滋生了严重的道德风险问题。文章基于医疗服务的信任品属性，利用实验方法刻画了商业保险和社会保险两种保险形式，并通过对比私人信息和公开信息探究了加强声誉建设对解决医疗保险“双刃剑”难题的作用。实验结果表明，首先，商业保险和社会保险均会导致医患双方的道德风险问题，且商业保险更严重。其次，声誉加强有利于缓解保险的道德风险，其作用机制在不同保险条件下有所不同。在商业保险条件下，声誉通过弥补患者的信息劣势，加大了对医生欺骗行为的约束；而在社会保险条件下，声誉在提振患者对市场的初始信心的同时，降低了患者因保险依赖而盲目交易的可能性。最后，综合医疗市场的经济效益和社会效益来看，公开信息商业保险和公开信息社会保险是两种相对高效的政策组合。

Can Reputation Solve the “Double-Edged Sword” Dilemmaof Medical Insurance: Evidence from an Experiment

As a typical credence goods, the medical market has huge information asymmetry between doctors and patients. In this kind of supplier-dominated market, although insurance is conducive to improving the accessibility and fairness of medical care, it also breeds moral hazard. This “double-edged sword” dilemma needs to be fixed with other market institutions. One of the possible solutions is to increase the transparency of medical information. Based on two common forms of medical insurance, social insurance and commercial insurance, we explore the effect of reputation on moral hazard induced by insurance. With a laboratory experiment, this paper provides policy recommendations for China's medical system and its supporting market institutions. We draw on a classic experimental framework of credence goods to simulate medical market, and design commercial insurance and social insurance in the experiment. Commercial insurance is characterized by that the expense out of threshold is shared by all policyholders. While under the condition of social insurance, the expense between the threshold and the reimbursement ceiling is borne by the government. We introduce the reputation in addition, which is divided into private information and public information according to the degree of information disclosure. Through the comparison between treatments, we can analyze the effects of different insurance and reputation institutions and their interactions on the performance of the medical market. The core experimental results of this paper are as follows, first, insurance has the “double-edged sword” dilemma, which both improves medical efficiency and induce moral hazard. Secondly, reputation only improves patients' consulting rate, but has no effect on inhibiting doctors' deceptive motivation. The combined effect of insurance and public information verifies that enhancing reputation is conducive to mitigating the moral hazard of insurance. Furthermore, the mechanism of reputation on the two insurance systems is different. Under the condition of commercial insurance, reputation help restrain doctors' fraud by making up for patients’ information disadvantages, which leads to maintain a stable level of honesty and interaction between doctors and patients. Under the condition of social insurance, strengthening reputation both increase patients' confidence of the medical market, and reduce the possibility of blind transactions by patients due to moral hazard. Finally, in view of the overall economic and social benefits of the medical market, enhancing reputation can help solve the “double-edged sword” problem of insurance. Public information with commercial insurance and public information with social insurance are two relatively efficient policy combinations. Based on the advantages of experimental method in causal identification，this paper first analyzes the interaction of different insurance and reputation. The results mentioned above have important inspiration for China's medical insurance reform. Both commercial insurance and social insurance have their own merits, and reputation is beneficial to alleviate the moral hazard dilemma. Therefore, politicians should also strengthen medical information disclosure to inhibit moral hazard problem when promoting comprehensive coverage of medical insurance.