【作者】 康传坤；

【导师】 楚天舒；

【作者基本信息】 西南财经大学 ， 西方经济学， 2014， 博士

【摘要】 人口老龄化日益加剧的背景下,许多国家都面临着养老金收支压力问题,特别是对于我国这个人口大国来说更是如此。为了缓解人口老龄化给养老金收支带来的压力,学者们提出了推迟退休年龄、提高缴费率、降低替代率及制度转轨等多种可供选择的解决途径。但是哪种途径能够有效的缓解养老金收支压力又能避免许多不利影响呢?对此,现有文献却缺少统一模型框架内的研究。针对这一不足之处,本文在一般均衡OLG模型框架内从理论上对不同途径的影响进行了分析。不过,从现实的角度来看,由于福利刚性,降低替代率的政策难以实施。而且,虽然有不少国家实现了制度转轨,但是其实际效果如何仍不清楚。因此,本文主要对推迟退休年龄和提高缴费率两种途径进行研究。在“统账结合”的养老金制度下,本文依据福利最大化原则首先测算了最优的平均退休年龄,并在此基础上考察了推迟退休年龄对经济系统的影响。最优平均退休的测算结果显示,人口老龄化背景下的最优平均退休年龄的变动区间为55.1—60岁,高于目前中国55岁的平均退休年龄。据此,我们认为应适当推迟退休年龄,这也是我国正在考虑实施的政策。推迟退休对经济影响的模拟结果表明,推迟退休年龄会降低稳态时的劳均资本存量、年轻人口消费及效用水平,但会提高老年人消费、社会统筹账户养老金水平及资本回报率。其次,本文根据福利最大化原则测算了最优社会统筹缴费率并考察了提高缴费率对经济系统的影响。最优缴费率的测算结果显示,人口老龄化背景下最优社会统筹缴费率的变动区间为10.22%——19.04%,低于当前20%的缴费率。仅从这一点来看,应适当降低统筹缴费率水平。但是,人口老龄化背景下如果没有充足的其他资金来源保障养老金支付,缴费率最终还可能会提高。从提高社会统筹缴费率对经济的影响来看,提高缴费率同样会降低劳均资本存量、年轻人口消费及效用水平,但提高社会统筹养账户老金收入水平及资本回报率。但与推迟退休年龄能提高老年消费不同的是,一定限度内提高缴费率能增加老年消费水平,但超过这一限度却会降低老年消费水平。从这一点可以看出,当其他条件不变时,推迟退休年龄的政策要优于提高缴费率的政策。上述结论是在人口增长率给定的情况下得出的,并没有考虑推迟退休年龄或提高缴费率对生育率的影响。如果推迟退休年龄或提高缴费率会导致生育率降低,那么没有充足人口进行缴费的养老金制度最终将无法持续。因此,本文最后考察了推迟退休年龄和提高社会统筹缴费率对生育率的影响。研究表明,推迟退休年龄将会降低生育率,但是会提高储蓄率和经济增长率。提高社会统筹缴费率也会降低生育率并提高经济增长率,但对储蓄率没有影响。总体来看,尽管差异不大,但推迟退休年龄的政策要优于提高缴费率的政策。不过,在实施推迟退休的具体政策时应充分权衡推迟退休带来的多方面影响,特别是对生育率的影响,以便根据政策目标把不利因素降到最低。本文的主要贡献之处在于构建了一个统一、可比较的模型框架对推迟退休年龄和提高缴费率两种缓解养老金收支压力的途径进行全面、系统、深入的比较,以便从理论上明确不同途径将对经济社会等多方面造成的影响。在此统一模型框架内,本文首次就推迟退休年龄对生育率影响的考察,更是为决策者在有关退休政策的制定上提供了新的洞见。更多还原

【Abstract】 Under the background of population aging, many countries are facing pension balance of payments pressures, especially more so for our country, In order to ease the pension payments pressure, scholars have proposed several alternatives such as postponing the retirement age, raising the contribution rate, decreasing replacement rate and the transition to a funded system. Which way can be effective to relieve pressure on pension payments and avoid many adverse impact? In this regard, the current study did not give an answer within the same model framework. In order to remedy the deficiencies, this paper theoretically investigates the effects of different pathway in an OLG model framework. However, from a practical point of view, it’s difficult to reduce the replacement rate due to welfare rigidity. In addition, although many countries have shifted to a funded system, but it remains unclear about the actual results. Therefore, this paper mainly focuses on two pathways:delaying the retirement age and increasing the contribution rate.Firstly, this paper estimates the optimal average retirement age according to the principle of welfare maximization, and on this basis, examines the economic impact of postponing retirement age under the pension system of social pooling and individual accounts. Estimation results show that, under the background of population aging the optimal average retirement age ranges from55.1to60, which is higher than the current average retirement age of55in China. Accordingly, we believe that the retirement age should be appropriately deferred, and it is also the policy that is to be implemented in China. Simulation results of delaying retirement age show that postpone the retirement age will reduce the capital stock per worker, consumption and utility level of the young, but will improve consumption and pension benefits of the elderly. Besides, it will also increase the return rate to capital.Secondly, this paper estimates the optimal contribution rates of social pooling accounts based on the principles of welfare maximization and then studies the effects of raising the contribution rate on the economic system. Calculation results show that, the optimal contribution rate changes among the range of10.22%-19.04%. Only from this point of view, the contribution rate should be appropriately reduced. However, if there is no adequate alternative sources of funding in order to guarantee the pension payments, the contribution rate is likely to be raised finally under the background of population aging. Simulation results of increasing the contribution rate show that, raise the contribution rate will reduce the capital stock per worker, consumption and utility level of the young, but improve the pension benefits and return rate to capital of the elderly. However, differently from delaying retirement age, if the contribution rate exceed a certain upper limit then raise the contribution rate will reduce the consumption of the elderly. From this point of view, it can be seen that when other conditions remain unchanged, the policy of postponing retirement age is superior to raising the contribution rate.When the population growth rate is constant, we can draw the conclusions above. But we ignore the impact of delaying retirement age or raising the contribution rate on fertility rate. If fertility will be reduced by postponing the retirement age or raising the contribution rate, then the lack of adequate population will eventually make the pension system unsustainable. Therefore, this paper finally examines the impacts of delaying retirement age and raising contribution rate on fertility rate. The results show that delaying retirement age will reduce the fertility rate, but it will increase the savings rate and economic growth rate. Raising the contribution rates will also reduce the fertility rate and increase economic growth rate, but has no effect on the savings rate.Overall, despite little difference, policy of postponing the retirement age is superior to raising the contribution rate. However, the government should fully weigh the impacts of postponing retirement age on economy and society, especially the impact on fertility rate when enact the specific policies of postponing retirement age so that minimize the adverse factors according to the policy objectives.The main contribution of the article is to construct a unified, comparable model framework, under which we conduct an comprehensive, systematic and in-depth comparison between delaying retirement age and increasing the pension contribution rate, so that we can understand theoretically the impacts of different approaches on economic and social aspects. Within this unified model framework, we investigate the impacts of postponing retirement age on fertility for the first time, which provide some new insights on for decision-makers on retirement policy.更多还原