信息不对称AsymmetricInformation(卫生经济学)I.pptVIP

信息不对称 Asymmetric Information 信息问题 Information Problems 患者——缺乏信息，也没有能力识别质量 Patients—lack of information and inability to discern quality 保险方——缺乏参保者的健康状况信息 Insurers—lack of information about individual’s health background 逆向选择 Adverse selection 假设有10个低风险的人和10个高风险的人，高风险的人预期的医疗保健费是1000美元，低风险的人预期的医疗保健费是100美元。医疗保险费的确定基于平均的预期医疗保健费，也就是550美元Suppose there are 10 low risk people and 10 high risk people, the high risk people’s expected health care expenditure will be $1000, the low risk’s will be $100. The health insurance premium is based on average expected expenditure, which is $550. 逆向选择 Adverse Selection 保险公司无法区分风险高和风险低的人。 保险费只反映了两类人的平均风险。因此高风险的人将购买保险，因为此时的保险费低于完全依照他们的风险确定的保险费。而低风险的人可能不会购买保险，因为此时的保险费高于完全依照他们的风险确定的保险费。 The insurance company is unable to distinguish between high and low risks. The insurance premium only reflects the average risk of the two groups. Then, the high risk group will purchase insurance since a premium based on the average risk is lower than a premium based solely on their own risk. The low risk individuals may not purchase insurance since a premium based on the average would be greater than their own risk-based premium. 逆向选择 Adverse Selection 逆向选择将会导致某些人购买医疗保险Adverse selection would result in a biased sample of those that purchase health insurance 更多的高风险个人将购买保险 Predominantly, more high risk individuals would purchase insurance “柠檬”法则 The Lemons Principle 高风险的人驱逐低风险的人直至市场不存在 The bad drives out the good until no market is left 柠檬法则 The Lemons Principle Akerlof (1970) 用信息不对称的观点分析二手车市场 Akerlof (1970) used the idea of asymmetric information to analyze the used car market 二手车的质量千差万别 Used cars available for sale vary in qualit