技术变化、劳动力流动与税制改革——多部门经济下如何设计所得税与商品税

How to Design Income and Commodity Taxes in a Multi-Sector Economy?-Enlightenment to China's Tax System Reform

本文在一个两部门内生工资,能力为私人信息,且劳动者在部门间自由流动的一般均衡模型中,研究了兼顾效率与公平的劳动所得税与商品税组合,以及一国税制应该如何随经济的变化而调整。考虑到部门间的技术差异、内生工资、人口流动和差异化的商品税,我们扩展了标准的Mirrlees税收公式。结论指出:①差异化的商品税可以通过缩小工资差距来促进收入再分配,此时高能力劳动者密集部门的商品税率应较高;②商品税率分摊了所得税的收入再分配职能,使得所得税的边际税率曲线变得较为平坦;③所得税与商品税税率均与收入的整体分布和要素间的替代弹性有关。作为本文研究的一个应用,我们基于2007年与2013年的中国城乡家庭收入调查数据进行了数值模拟。分析发现:随着部门间收入差距的缩小和部门内部收入差距的扩大,部门间商品税税率差距应缩小,而所得税在收入再分配中的作用将变得更加重要。若将农业部门的税率视为零,本文结论说明:相比于2007年,2013年非农商品的最优税率在下降,同时最优所得税在高收入段的累进性应提高。此外,本文还说明了为何对低收入段征收的边际税率不宜过低。

In a dual economy with a continuum of endogenous wages,we provide both optimal income tax and commodity tax formulas with sufficient statistics.We treat the sector with higher income and lower substitution elasticity between labor factors as urban areas,while the other one as rural areas.We find that both commodity and income tax depend on wage elasticities with respect to labor inputs.Higher commodity tax rate should be levied on the goods produced by high-ability individual relative intensive sector,which in turn makes income tax flatter.Considering endogenous wages,labor mobility and commodity taxes,we generalize the standard optimal income tax formula.The numerical simulation is based on a survey data on urban and rural household income in China in 2007 and 2013.We find that urban commodity tax is always higher than rural commodity tax,while the difference is relatively smaller in 2013.Besides,given the substitution elasticity between labor factors in urban areas,the difference between the commodity tax rates of urban and rural areas are increasing with the decrease of substitution elasticity in rural area.