工薪所得税及其改革的公平效应——基于K指数的实证检验

The Equality Effect of Wage Income Tax and Its Reform:An Empirical Test Based on Kakwani Index

通过分解税制要素的K指数,对工薪所得税公平效应进行了改革前后的纵向比较和税制要素的横向比较。研究发现,我国的工薪所得税对社会公平具有整体的微弱促进效应,但2011年的税制改革侵蚀了工薪所得税的公平效应;就税制要素而言,税率和免征额有利于收入公平,社会保障扣除不利于收入公平;在不同收入水平下,社会保障扣除的逆向调节程度随着纳税人收入增加而降低,同时社会保障扣除的不同项目对居民收入分配的逆向调节程度不同,其中住房公积金的逆向调节效应最为明显。因此,今后应重视工薪所得税的公平效应,充分发挥其收入公平分配作用;合理设定工薪所得税的免征额,提高税收累进性;完善社会保障扣除制度,并统筹设计税收与转移支付制度体系。

By decomposing the K ind ex of taxation elements, this paper makes a vertical comparison on the equality effect of wage income tax between before and after the reform and a horizontal？comparison between different taxation elements. The empirical result shows that China＇s wage income tax has a weak stimulation effect on the social equity as a whole, but the tax reform in 2011 was harmful to it. As for the taxation elements, the tax rate and the tax exemption volume are in favor of income equality, while the social security deduction has the reverse effect. Under different income levels, the reverse adjustment degree of social security deductions decreases with the increasing income of the taxpayers. Meanwhile, the different items of social security deduction have different reverse adjustment levels on the residents＇ income distribution, in which the housing accumulation fund has the most obvious reverse adjustment effect. Therefore, it is suggested that in the future more attention should be paid to the equality effect of wage income tax so as to give full play to its role in fair income distribution; the tax exemption volume of the wage income tax should be determined rationally so as to improve its progressivity; the social security deduction system should be improved, and a tax-transfer payment system should be designed in an overall manner.