生育政策调整、退休年龄延迟与城镇职工基本养老保险最优缴费率

文章基于“十三五”规划建议提出适当降低社会保险费率的现实背景，从社会福利最大化视角，运用一般均衡模型对五种生育情景下不同退休年龄的城镇职工基本养老保险最优社会统筹缴费率进行测算，并分析降低社会统筹缴费率的经济效应。研究表明：（1）最优社会统筹缴费率随退休年龄的延长而下降，随人口增长率的上升而提高。0％－100％符合全面二孩政策规定的妇女生育二孩，使退休年龄为60岁时的最优社会统筹缴费率降到191．8％－196．3％，使退休年龄为65岁时的最优缴费率降到107．7％－116．4％。（2）除了受生育政策和退休年龄影响外，最优社会统筹缴费率对物质资本产出弹性、个人主观效用贴现因子和社会贴现因子的敏感性也较强。（3）降低社会统筹缴费率具有积极的经济效应，不仅能促进经济增长和增进社会福利，而且有助于完善我国多层次养老保险体系。因此，文章为降低城镇职工基本养老保险社会统筹缴费率的改革提供了依据。

Fertility Policy Adjustment,Retirement Age Extension and Optimal Contribution Rate of State Basic Pension Scheme for Urban Employees

In the background of the 13th Five-Year Plan proposing that it is appropri‐ate to reduce the rate of social insurance ,this paper calculates the optimal contribution rate of basic pension insurance system for urban residents in the five types of fertility context u‐sing a general equilibrium model from the perspective of social welfare maximization ,and analyzes the economic effect of the reduction in social pooling contributions .It comes to the conclusions as follows :firstly ,the optimal social pooling contribution rate goes down as the extension of the retirement age and increases with the rise in population growth rate ;as the percentage of eligible women having a second child ranges from 0% -100% ,the op‐timal contribution rate decline to a level of 19 1.8% -19 6.3% under a retirement age of 60 years old ,and to a level of 10 7.7% -11 6.4% under a retirement age of 65 years old .Sec‐ondly ,besides fertility policy and retirement age ,the optimal contribution rate is also sen‐sitive to physical capital output flexibility ,personal subjective utility discount factor ,and social discount factor .T hirdly ,the reduction in the social pooling contribution rate has a positive economic effect ;it not only promotes economic growth and social welfare ,but al‐so contributes to the multi-tier pension insurance system .Therefore ,it provides the evi‐dence for the reform of the reduction in the contribution rate of basic pension insurance system for urban residents in China .