收入再分配政策调节机制的探讨

The Discussion on the Regulatory Mechanisms of Income Redistribution Policies

虽然同为再分配政策工具,个人所得税和社会保障支出(也即转移支付)存在诸多差别,其中之一是再分配效应的相对大小,具体而言,转移支付的再分配效应远远大于个人所得税。围绕两种政策工具的调节收入分配功能,本文首先探索了两种政策工具再分配效应相差悬殊的根源,然后通过考察政策工具规模和累进性的关联,探讨了两种政策工具调节收入分配的机制及其异同。本文的主要结论有:第一,累进性是两种政策工具再分配效应相差悬殊的主要原因,即转移支付的累进性取值远远超过个人所得税,最终导致转移支付的再分配效应远远大于个人所得税。第二,对于个人所得税规模(平均税率)和累进性的相关关联,一方面,规模和累进性之间存在负相关关系,即累进性随个税平均税率的提高而减弱,二者是互为抵消的关系;另一方面,在决定个税再分配效应上,规模因素较累进性更重要,因此在保证累进性的前提下,提高个人所得税平均税率是发挥个税再分配调节作用的关键。第三,转移支付的规模(转移支付率)和累进性存在正相关关系,即随着社会保障支出规模的增加(即转移支付率的提高),社会保障体系对低收入人群的瞄准性会逐步得到改善,二者是互为增强的关系;在扩大社会保障支出规模的同时,有意识地将资金分配向低收入人群倾斜,是社会保障支出发挥再分配功能的关键,也是社会保障体系发展的一般规律。

It is well known that income redistribution policies have two tools:personal income tax and social security expenditure,with the latter also known as transfer income.Although both are tools of redistribution policies,personal income tax and social security expenditure are completely different in the way of working on income distribution.Personal income tax plays a role in limiting the income of high-income groups.In contrast,social security expenditure provides transfer payments for low-income populations through public pensions,medical insurance,and minimum living allowances,thereby raising the relative income level of low-income populations.Previous literature on income redistribution has focused on the methodology of measuring redistribution effects and measurements of redistribution effects in various countries using household survey data.The Kakwani decomposition of redistribution effects is a representative study of the former,while the latter is concentrated on the study of OECD members.The emergence of the Luxembourg Income Study Database(LIS)has greatly stimulated the measurement of redistributive effects in various countries.For example,an OECD study showed that around 2013,redistribution policies in 25 OECD members reduced the average market income Gini coefficient of the working-age population by more than 25%,with transfer payments accounting for 3/4(75%)and personal income tax accounting for 1/4(25%).The size of the redistribution effect is positively correlated with the level of economic development.Redistribution is the main reason why the per capita disposable income Gini coefficients in developed countries are lower than those in developing countries,while the market-determined Gini coefficients(i.e.,income gaps before redistribution policy intervention)do not show a clear correlation with the level of development.Previous literature focusing on methodology and measurement has overlooked the study of mechanisms of redistribution policies working on income distribution.Why is the redistribution effect of transfer payments far greater than that of personal income tax?As tools of redistribution policies,what are the relative advantages and disadvantages of the two?The Kakwani decomposition shows that the redistribution effect is mainly determined by two factors:the scale and progressivity of the policy.So which is more important,scale or progressivity?At the policy implementation level,should more attention be paid to policy scale or progressivity?These issues related to the mechanism of the redistribution process have not received sufficient attention so far,which is precisely the focus of this paper.Thus,this paper first explores the reasons for the stark difference in redistribution effects between the two policy tools,and then examines the association between the scale and progressivity of policy tools(including relative importance and correlation).The main conclusions of this paper are as follows.First,progressivity is the main source of the stark difference in redistribution effects between the two policy tools,i.e.,the progressivity of transfer payments far exceeds that of personal income tax,ultimately leading to a much larger redistribution effect of social security expenditure than personal income tax.Second,regarding the correlation between the scale(average tax rate)and progressivity of personal income tax,on the one hand,there is a negative correlation between scale and progressivity,meaning that progressivity decreases as the average tax rate increases,with the two offsetting each other.On the other hand,in determining the redistribution effect,the scale factor is more important than progressivity.Therefore,the key to enhancing the redistributive effect of personal income tax is to increase the average tax rate while ensuring its progressivity.Third,there is a positive correlation between the scale(transfer payment rate)and progressivity of transfer payments,meaning that as the scale of social security expenditure increases,the targeting of the social security system towards low-income groups gradually improves,with the two reinforcing each other.While expanding the scale of social security expenditure,allocating funds towards lowincome groups as much as possible is key to enabling social security expenditure to play a redistribution role and can be regarded as a general rule of the redistributive function of social security.