存在收入差异的社会保障制度选择——基于一个内生增长世代交替模型

A Welfare Analysis of Social Security in An Economy with Income Inequality:Based on An Overlapping Generation Model of Endogenous Growth

社会保障制度选择是经济协调发展中的重要课题。本文建立了一个考虑存在收入差距的异质性个体的内生增长世代交替模型，综合考察了社会保障制度选择对经济增长和收入再分配的影响。分析表明，现收现付制对稳定状态的经济增长率有负面影响，但其收入再分配功能对提高社会总福利存在正向作用，通过数值模拟发现当收入差距较小时，现收现付制对经济增长的抑制作用较强，随着收入差距的拉大，收入再分配功能将逐渐居于主导地位，其综合效应可以改善社会福利。在一定的收入差异程度范围内，存在一个使社会福利最大化的最优现收现付制比率。基于对中国实际的分析，本文认为我国未来的社会保障制度改革应该注重发挥现收现付制的再分配功能。

This paper studies the effects of social security on economic growth and income redistribution. We construct an endogenous growth model with heterogeneous individuals that differ in income levels. We show that a pay-as-you-go （PAYG） system has adverse effects on growth in the steady state, but has positive effects on income redistribution within generations. Our numerical simulation suggests that the adverse effect of the PAYG system is weaker when income inequality is larger. This paper suggests that the redistributive effects of the PAYG system should be fully recognized in China＇s social security reform.