养老保险可持续性、社会福利和养老金最优缴费率研究

A Study on the Sustainability of Pension Insurance,Social Welfare,and the Optimal Payment Rate of Pensions

本文基于个人效用函数以及社会福利函数研究了我国养老保险个人账户和统筹账户缴费率的最优值,并基于养老保险收支平衡的精算模型测算了当养老保险的缴费率达到最优值时养老保险的可持续性,在此基础上,探究了在保持个人效用和社会福利不变的情况下,能否通过个人账户缴费率和统筹账户缴费率之间的替代关系提高养老保险的可持续性,从而兼顾养老保险的可持续性和社会福利水平。本文研究结果表明:现行养老保险制度的个人账户缴费率和统筹账户缴费率低于福利最大化的个人账户最优缴费率和统筹账户最优缴费率;个人账户最优缴费率和统筹账户最优缴费率对人口增长率的敏感度较低,对资本产出比的敏感度较高;统筹账户缴费率与个人账户缴费率具有替代关系,可以通过降低养老保险统筹账户缴费率的同时提高个人账户缴费率的方式实现更高程度的养老保险可持续性。

Based on the individual utility function and social welfare function,this paper calculates the optimal value of the contribution rate of China’s pension individual account and pooling account,and calculates the sustainability of the pension when the contribution rate reaches the optimal value based on the actuarial model of pension revenue and expenditure balance,and evaluates the sustainability of the pension when the individual utility and social welfare remain unchanged,whether the sustainability of pension can be improved through the substitution relationship between individual account contribution rate and pooling account contribution rate.The results of this study show that the individual account payment rate and the pooling account payment rate of the current pension insurance system are lower than the optimal individual account payment rate and the pooling account payment rate of the welfare maximization;The optimal contribution rate of individual account and the optimal contribution rate of pooling account are less sensitive to population growth rate and more sensitive to capital output ratio;There is a substitution relationship between the contribution rate of the pooling account and the contribution rate of the individual account.A higher degree of pension sustainability can be achieved by reducing the contribution rate of the pooling account and increasing the contribution rate of the individual account.