基于异质性世代交替模型数值模拟的个人所得税改革分析

The Effects of Personal Income Tax Reform Based on an OverlappingGeneration Model with Heterogeneous Individuals

本文在引入异质性个体的世代交替模型的基础上,加入税收收入中性约束,通过数值模拟实验讨论简化个人所得税累进税级和二元所得税课税模式对收入分配和经济增长的影响。个人所得税累进税级设置在收入、财富分配与经济增长间存在取舍关系。一个七级累进的个人所得税制度与单一所得税的对比模拟实验表明,政府能通过调整单一所得税的免征额达到与累进税一样的收入分配效果,同时保持增长率几乎不变。本文通过基尼系数之比、增长率之比和税率与免征额之间的关系,展示了政府的单一所得税改革的政策选择空间。二元所得税课税模式相比综合所得税课税模式,更鼓励个体投资教育,增加人力资本积累,从而有利于经济的长期增长。

In this paper, we discuss the impacts of personal income tax reform on the macroeconomic and the optimal choices of individuals based on an overlapping generation model with heterogeneous agents. We find that the government faces the tradeoff between efficiency and equality when deciding the progressivity of personal income tax. We simulate the reform of a 7 graduated income taxation system to a flat one, and we find that the government can obtain the same tax progressivity and almost the same economic growth ratio simultaneously by adjusting the exemption of the flat tax. We demonstrate the government＇s policy choice space of the flat tax reform by portraying the connection of the ratios of Gini coefficient and economic growth between two tax systems and the relation between exemption and tax rate. Compared with the comprehensive tax, the dual income tax more encourages individuals to invest on education, so it can increase the accumulation of human capital and is beneficial to the long run economic growth.