代际流动约束下生育率与收入不平等关系的国际检验

收入不平等问题和人口生育率过低问题是当下中国面临的两大难题,但目前理论界关于人口因素与收入不平等关系的研究,很少从生育率视角来考察以及考虑代际收入流动在其中的作用.文章从理论与经验两个方面来考察生育率对收入不平等的影响,理论模型表明:在关于代际收入流动的假设下,一个经济体中生育率的提高会使穷人比重提高,进而拉大收入不平等.进一步地,文章利用1970-2011年76个国家(地区)面板数据的经验研究发现:(1)总和生育率的提高会拉大收入不平等,如果每个妇女平均多生育一个孩子,将会使基尼系数增加0.025;(2)以出生率作为总和生育率替代指标的实证结果与基准结果基本一致,这说明不同生育率测算指标高度相关且可相互替代;(3)对于代际收入流动弹性越高、收入水平越低或生育率越高的国家(地区),其生育率提高对收入不平等的拉大作用越大.文章关于生育率对收入不平等影响的作用机制和异质性特征的考察,对于我国如何在实施"全面二孩"政策下寻求应对严峻的收入分配问题之策提供了国际经验和启示.

An International Study on the Relationshipbetween Fertility Rate and Income Inequalityunder the Constraint of Intergenerational Mobility

The problems of income inequality and low fertility rate are two major challenges in China nowadays.However, there are few researches about the relationship between demographic factor and income inequality from the perspective of fertility rate and exploring the role of intergenerational income mobility in the academia.This paper theoretically and empirically explores the impact of fertility rate on income inequality.The theoretical analysis shows that an increase in fertility rate will increase the proportion of the poor, thus enlarging the income inequality in an economy under the assumption of the intergenerational income mobility.Furthermore, using a cross-country panel dataset covering 76 countries and regions between 1970 and 2011, our empirical findings show as follows: firstly, an increase in total fertility rate will lead to a rise in income inequality;specifically speaking, if each woman has one more child on average, the Gini coefficient will increase by 0.025;secondly, the results by using the birth rate as a proxy indicator for total fertility rate are identical with the basic results, which mean that different measurement indicators for fertility rate are highly correlated with each other and can be mutually substituted;thirdly, total fertility rate has a greater impact on income inequality in countries with higher level of intergenerational income mobility elasticity, lower level of income, or higher level of total fertility rate.The analysis of the mechanism and heterogeneous characteristics of the effect of fertility rate on income inequality provides international experience and enlightenment for how to deal with the serious income distribution issue under the universal two-child policy.