延迟退休对职工效用最大化的影响——基于“S”型效用函数的分析

"十四五"规划提出"实施渐进式延迟法定退休年龄",如何使延迟退休政策被大众广泛接受是我国养老保险制度改革的重点问题。基于个人效用最大化原理,结合我国现行养老保险制度和前景价值函数中的"S"型效用函数,构建关于工资收入、养老保险缴纳费用、养老金财富和闲暇时间的综合效用模型,从性别、闲暇偏好、工资收入水平、利率、参保年龄、养老金个人缴费率六个方面确定个人效用最大化的退休年龄,并结合我国当前国情,对延迟退休政策提出针对性的建议。研究结果表明:不同退休年龄下的个人效用函数是关于退休年龄的"先大幅上升,后缓慢下降"曲线。男性参保职工于63岁退休获得效用最大值,而女性参保职工于60岁退休获得效用最大值,且二者最优退休年龄并不会随工资收入水平的改变而改变,工资收入水平只会对参保职工获得的效用绝对值产生影响,工资收入水平越高,参保职工获得效用值越大。此外,若闲暇偏好越低、利率越低、参保年龄越大、养老保险个人缴费率越低,则参保职工的最优退休年龄就越大。总体而言,只有考虑性别因素、给予延迟退休政策适当的弹性操作空间、改进养老保险计发办法、创造更好的老年就业环境,才能使延迟退休政策更好地推行。

The Impact of Delayed Retirement on Employee Utility Maximization: Based on S-type Utility Function Analysis

The“Fourteenth Five-Year-Plan”proposes to“implement the gradual deferment of the legal retirement age”.How to make the policy of deferring retirement widely accepted by the public is the key issue in the process of China’s endowment insurance system reform.Based on the theory of individual utility maximization,combined with China’s current endowment insurance system and S-type utility function in prospect value function,this paper constructs a comprehensive utility model associated with wage income,insurance payment,pension wealth and leisure,and determines the retirement age to maximize individual utility from the aspects of gender,leisure preference,wage income level,interest rate,insurance age and individual contribution rate of endowment insurance.Then it puts forward targeted suggestions on the policy of deferring retirement in combination with China’s current national conditions.The results show that the individual utility function under different retirement ages is a curve about retirement age,which first rises sharply and then decreases slowly.Male employees get the maximum utility when they retire at the age of 63,while female employees get the maximum utility when they retire at the age of 60.Meanwhile,the optimal retirement age of the insured and the insured does not change with the change of wage income level,which only affects the absolute value of utility obtained by insured workers.The higher the wage income level,the greater the utility value obtained by insured employees.In addition,the lower leisure preference,lower interest rate,older the insured age and lower the individual contribution rate of endowment insurance can result in the older the optimal retirement age of insured employees.In general,in the implementation of gradual retirement policy,only by considering gender factors,giving appropriate flexible operation space to the delayed retirement policy,improving the pension insurance payment method and creating a better employment environment for the elderly can make policy implication better.