1986年—2009年中国城镇地区的收入阶层划分与收入不平等——基于有限混合模型的测算

Households Income Class Division and Income Inequality in Urban Areas of China——based on Finite Mixed Model

基于1986年—2009年中国城镇住户调查详尽的微观数据,本文使用FMM模型将历年样本中的家庭内生聚类为高、中、低三类收入阶层,并利用MLD指数的计算及分解方法分析了历年各个收入阶层之内以及不同收入阶层之间的收入不平等程度,及其对总体收入不平等程度的贡献大小。研究的主要结论包括:第一,尽管总体呈下降趋势,但低收入阶层占比仍然较大超过了50%,而且高收入阶层收入水平的上涨速度要远高于中、低收入阶层;第二,不同地区的收入阶层分布存在显著差异;第三,中国城镇地区的整体收入不平等程度表现出三阶段特征,低收入阶层的收入不平等程度一直都高于其他收入阶层;第四,组间收入不平等是目前中国城镇地区总体收入不平等的主要影响因素,低收入阶层的组内收入不平等贡献率始终要远高于其他收入阶层。如果上述趋势延续至今,那么调节收入分配的政策仍然十分必要,并尤其应当提高低收入阶层的收入水平以缓解中国的收入不平等问题。

Based on the detailed micro-data of the urban household survey in China from 1986 to 2009,this paper uses the FMM model to endogenously cluster households into high,middle and low income classes,and uses the calculation and decomposition method of MLD index to analyze the income inequality within each income class and between different income classes and their contribution to the overall income inequality.Below are the main conclusions of the paper.First,despite the overall downward trend,the proportion of low-income class is still more than 50%,and the income level of high-income class rises much faster than that of middle-and low-income class.Second,the distribution of income classes in different regions shows significant difference.Third,the overall income inequality in China’s urban areas shows a three-stage characteristic,and the income inequality of the low-income class has always been higher than that of other income classes.Fourth,income inequality between classes is currently the main influencing factor of overall income inequality in urban areas of China.The contribution rate of income inequality within low-income class is always much higher than that of other income classes.If the above trends continue,we believe that policies to regulate income distribution are still very necessary,and especially the income level of the low-income class should be raised to alleviate China's income inequality.