中文摘要
我们在一个一般均衡世代交叠模型中研究个人所得税的最优累进性，在该模型中，个体在生命周期内受到劳动生产率和健康状态的异质性冲击。我们的结果——基于对美国经济的校准——表明，健康风险的存在和可用的保险制度均对最优税收累进水平有强烈影响。考虑到美国碎片化且非全民覆盖的医疗保险制度，福利最大化的所得税制比当前美国所得税制具有显著更高的累进性。更高的累进性提供了额外的再分配和社会保障，特别是对于获取医疗保险途径有限的不健康低收入个体。当通过引入更全面的医疗保险制度来消除或减少对健康风险的暴露时，我们观察到最优所得税累进水平的大幅下降，且最优税制与先前文献的发现相似。这些发现凸显了在刻画最优所得税时考虑健康风险独特特征和医疗保险制度设计的重要性。
Abstract
Abstract We study the optimal progressivity of personal income taxes in a general equilibrium overlapping generations model where individuals are exposed to idiosyncratic shocks to labor productivity and health status over the lifecycle. Our results—based on a calibration to the US economy—indicate that both, the presence of health risk and the available insurance institutions, have a strong effect on the optimal level of tax progressivity. Given the fragmented and non-universal health insurance system in the US, a welfare maximizing income tax system is substantially more progressive than the current US income tax. The higher progressivity provides additional redistribution and social insurance, especially for unhealthy low income individuals who have limited access to health insurance. When exposure to health risk is removed or reduced by introducing more comprehensive health insurance systems, we observe large decreases in the optimal level of income tax progressivity, and the optimal tax system resembles findings from the previous literature. These findings highlight the importance of accounting for the unique characteristics of health risk and the design of the health insurance system when characterizing optimal income taxes.