人口流动如何引起地区养老保险成本不平衡

How Population Mobility Causes Regional Imbalances of Pension Cost?

为什么中国经济发达地区的养老保险费率低于经济欠发达地区?对于这一有悖直觉的现象,本文利用全国287个地级以上城市样本,结合历次全国人口调查数据,分析人口流动引致地区养老成本不平衡的传导机制,给出了合理解释。本文的研究发现,改革开放以来中国劳动力持续大规模流动引起城市人口年龄结构变动,外来人口比重变动可以解释地区老年人比重变动的26%,外来人口比重上升显著降低地区老年人比重,人口的流出显著提升了地区老龄化程度。人口流动引致的地区老龄化程度差异带来不同的地区财政压力,人口流出地政府倾向于采用或维持较高的养老保险费率和缴费基数,人口流入地则相反。本文揭示了人口流动、人口年龄结构与养老保险成本地区差异间的因果联系,有助于人们理解中国养老保险成本地区不平衡的历史成因。

Why are pension contribution rates in the developed regions significantly lower than those in the less developed regions?Based on a sample of 287 Chinese cities and data from multiple national population surveys,this paper adopts several empirical strategies to analyze the transmission mechanism of regional imbalance in pension cost due to population mobility.It finds that the continuing large-scale labor force migration in China since the reform and opening-up has introduced considerable changes in the regional population structure,and migrant population can explain 26 percent of the variation in the proportion of elderly population among regions.The inflow of migrant population significantly reduces the aging level in a region,while the outflow of population does the opposite.The different levels of aging associated with population mobility brings about different degrees of fiscal pressures.While the local governments of the outflow regions have to maintain high pension contribution rate facing increased fiscal pressures,the regions with population inflow can cut the rate.This paper clarifies the causal relation among population movement,demographic structure,and the regional imbalance of pension costs,and it helps with understanding historical sources of regional differences in pension costs.