《保险研究》20200609-《医疗保险的道德风险研究——基于补偿政策变动的经验证据》（向辉、杜创、彭晓博）

［摘   要］本文利用中国东部某相邻两县基本医疗保险由县区统筹向市级统筹转变过程中，补偿政策调整差异的“准实验”,基于全样本的微观住院支出与医保报销面板数据,使用双重差分模型识别和估计医疗保险道德风险。研究结果显示,医保补偿比率提高导致住院费用显著上涨,抵消了报销费用提高的部分,使患者自付支出并未显著降低。医保目录内外费用结构、医疗机构级别、年龄、疾病类型等异质性分析表明,乡镇级、县级、市级等不同级别医疗机构的费用效应存在显著差异,其中乡镇级费用效应最强,其次为县级和市级。从需方角度看,需求价格弹性的非线性特征、就医交通成本、年龄分布差异等均有助于解释上述异质性。从供方角度看,提高保险补偿比率后,医保目录内外费用结构的变化、县内和县外、慢性病和非慢性病之间的费用效应差异均揭示了供方道德风险。

［关键词］医疗保险；道德风险；补偿政策；双重差分

［基金项目］北京市自然科学基金青年项目(9194032)和教育部社科青年基金项目(17YJC790116)。

［作者简介］向辉,清华大学公共管理学院博士研究生；杜创,中国社会科学院经济所微观经济学研究室主任,研究员；彭晓博,中央财经大学经济学院讲师。

Moral Hazard of Health Insurance based on Empirical Evidence from Compensation Policy Change

XIANG Hui,DU Chuang,PENG Xiao-bo

Abstract：A compensation policy change of two adjacent counties in the east of China provided a rare opportunity for the quasi-natural experiment to measure the moral hazard effect of health insurance.The study used the detailed panel data of individual hospitalization expenses and insurance claims payment to estimate the effect of moral hazard in health insurance with the Difference-in-Difference method.The result shows that the increase in the ratio of compensation of the New Cooperative Medical Insurance Plan causes a significant increase in hospitalization fees,which offsets the increase in the reimbursable expenses.As a result,the patient′s out-of-pocket fees are not visibly decreased.By measuring the heterogeneity of moral hazard at different levels of medical facilities,different age groups,and different diseases and for social medical insurance category listed or non-listed expenses structure,the study finds that the expense effect is significantly different for medical facilities at the township,county and city levels from the strongest to the least.From the demand side,the non-linearity of the demand price elasticity,transportation costs for accessing medical services,and difference in age distribution all help to explain the existence of the abovementioned heterogeneity.From the supply side,the change in social medical insurance category listed or non-listed expenses structure,and the expense effect difference within and without the county,and between chronical or non-chronical diseases after the compensation ratio increase can expose the moral hazard of the supply side.

Key words：social medical insurance;moral hazard;compensation policy;Difference-in-Difference method