On the optimal design of pension systems

The present paper aims to quantify efficiency properties of flat and earnings-related pay-as-you-go financed social security systems of various institutional designs in order to identify an optimal pension design. Starting from a benchmark economy without social security, we introduce alternative pension systems and compare the costs arising from liquidity constraints as well as distortions of labor supply versus the benefits from insurance provision against income and lifespan uncertainty. Our findings suggest an optimal replacement rate of about 50 % of average earnings. In our model a single-tier earnings-related pension system yields the highest efficiency gains dominating flat benefits as well as two-tier systems of any form. We also show that the negative correlation between pension progressivity and pension generosity of real-world social security systems can be justified on efficiency grounds. Finally, our results indicate a positive impact of means-testing flat benefits against earnings-related benefits within multi-pillar pension systems.     

Health Status Risks and the Efficiency of Social Security Systems

We studied the allocative efficiency of a social security system with earning tests focusing on the leisure–work choices of older men. Given empirical findings that health status and social security benefits are the most important determinants of such choices, we incorporated risks with respect to health status into an overlapping–generations model, and analysed how allocative efficiency was changed by the introduction of social security systems. It was found that the effects of a social security system can be broken down into particular categories and that a social security system improves efficiency when the pension system is small. JEL Classification Numbers: H55, I10, E40.     

Social security and risk sharing

In this paper we identify conditions under which the introduction of a pay-as-you-go social security system is ex ante Pareto-improving in a stochastic OLG economy with capital accumulation and land. We argue that these conditions are consistent with realistic specifications of the parameters of the economy. In our model financial markets are complete and competitive equilibria interim Pareto efficient. Therefore, a welfare improvement can only be obtained if agents? welfare is evaluated ex ante, and arises from an improvement in intergenerational risk sharing. We also examine the optimal size of a given social security system as well as its optimal reform.     

社会保障的新理念与中国农民扶持性社会保障体制

中国的市场化改革使广大的中国农民直接暴露在现代市场经济风险下,而家庭联产承包制的实施又使改革开放前与计划经济体制相适应的保障体制无法运转,这样,中国广大农民成为了现代市场经济中最没有保障的弱势群体。因此,建立农民社会保障体系的意义重大。中国农民社会保障体制迟迟没有建立的原因有二:其一,传统社会保障理念仅考虑到其工具价值,忽视了其目的价值;其二,农民的组织化程度低,导致他们在社会利益分割过程中没有谈判地位。从建立农民社会保障体制的双重价值出发,建立保障农民生存权和基本发展权的农民扶持性社会保障体制具有重要意义。     

Social Security Strategies and Redistributive Effects in European Social Transfer Systems

This paper evaluates the linkage between social security strategies and redistributive effects in EU social transfer systems. It is argued that the various European systems produce different patterns of redistribution that may be explained by the adoption of different mixes of social security strategies. In support of this argument, several ideal-typical strategies are characterized and a classification of European social transfer systems is introduced. Subsequently, the redistributive effects of the systems are assessed and the relationship to their class assignment is investigated. We conclude that the redistributive effects differ markedly between systems of different classes, indicating that redistributive patterns are heavily influenced by the adopted strategy mix.     

Social Security, Optimality, and Equilibria in a Stochastic Overlapping Generations Economy

Social security institutions implement intergenerational transfers and distribute risks over time. To compare various social security designs, we study an overlapping generations model with demographic shocks. Production takes place through a neoclassical production function subject to productivity shocks. We give a near characterization of optimal allocations. We study rational expectations equilibria when contributions are mandatory, based on labor and capital income. We also describe the equilibria of an economy with a voluntary pay-as-you-go social security fund, and show that they have a long-run optimality property. An example with Cobb–Douglas production and utility functions illustrates the results.     

Optimal Taxation when Consumers Have Endogenous Benchmark Levels of Consumption

I examine optimal taxes in an overlapping generations economy in which each consumer's utility depends on consumption relative to a weighted average of consumption by others (the benchmark level of consumption) as well as on the level of the consumer's own consumption. The socially optimal balanced growth path is characterized by the Modified Golden Rule and by a condition on the intergenerational allocation of consumption in each period. A competitive economy can be induced to attain the social optimum by a lump-sum pay-as-you-go social security system and a tax on capital income.     

Quasi-hyperbolic discounting and social security systems

Hyperbolic discounting has become a common assumption for modeling bounded rationality with respect to individual savings decisions. We examine the effects of hyperbolic discounting on the comparison of alternative social security systems. We show that this form of bounded rationality breaks the equivalence between funded and pay-as-you-go (PAYG) systems established in Sheshinski and Weiss [Sheshinski, E., Weiss, Y., 1981. Uncertainty and optimal social security. Quarterly Journal of Economics 95, 189-206]. Intergenerational transfers within a PAYG economy are usually secured by the social security system and independent of longevity, whereas this is not the case for the funded economy. The savings level under hyperbolic discounting is lower than under exponential discounting [Laibson et al., 1998], but the ratio between the savings level under hyperbolic discounting within a funded economy and a PAYG economy depends on the effectiveness of the commitment devices. It is shown that if individuals are hyperbolic discounters, then in a PAYG economy any change in the mandated level of intergenerational transfers is neutralized by individuals’ voluntary bequests. This does not apply to a funded system.     

Optimal social security tax with myopic agents

Myopic agents lack the foresight to save for their own old age. It is generally believed that correcting myopia is a rationale for a pay-as-you-go (PAYG) pension system. This view has been supported by existing literature showing that the optimal PAYG social security tax should increase when people are more myopic. In this paper we obtain new results opposed to the traditional view. By establishing a very standard general equilibrium OLG model with myopic agents and endogenized marginal product of capital, we show that the optimal social security tax should be lower when people are more myopic. Our numerical analysis also shows that the welfare cost of the social security tax increases with people's degree of myopia. These results suggest that correcting myopia is not a clear rationale for the PAYG social security.     

中国传统文化信念、人力资本积累与家庭养老保障机制

本文首先构建一个人力资本积累模型,考察传统文化信念驱动下的家庭养老保障机制以及社会养老保障制度对家庭养老和人力资本投资行为进而对经济增长的影响。分析表明,传统文化信念将后代人力资本积累与父代养老保障有机地联系起来,提供了一种很好的家庭养老保障和人力资本内生积累机制;现收现付型社会养老保障制度不利于人力资本积累和经济增长。其次,本文以我国现实数据为基础进行实证研究,得到结论是社会养老保障制度对我国人力资本积累和经济增长具有明显的抑制作用,而家庭养老保障机制的良好运转则有助于更好地促进人力资本积累和经济增长。因此,我国在致力于完善社会养老保障制度的同时,决不能忽视家庭养老保障机制的作用与培育。     

On myopia as rationale for social security

It has been argued that “paternalistically motivated forced savings constitutes an important, and to some the most important, rationale for social security retirement systems.” This paper revisits the role played by myopia in generating a theoretical rationale for pay-as-you-go (PAYG) social security in dynamically efficient economies. If the competing asset is linear storage and myopic agents are allowed to borrow against future pension benefits, there is no welfare-rationale for PAYG pensions. Sufficiently strong myopia may justify such pensions only if agents cannot borrow against their future pension, but then they are at a zero-saving corner. With enough myopia, co-existence of positive optimal pensions and positive private saving is possible if the return to saving declines with saving, as in a model with a neoclassical technology.     

关于农民工社会保障问题的思考

从农民工社会保障现状出发,通过对农民工社会保障公平性和制度设计的思考,强调农民工社会保障构建的必要性和探索农民工社会保障制度在实施中的可行性。在目前还不具备建立一元社会保障制度——且一元社会保障在差别社会未必是公平社会保障模式的情况下,应构建以长期目标与城镇社会保障体系接轨的,以"底线保障"为基础的,柔性过渡的分类分层农民工社会保障制度模式。     

我国机关事业单位养老保险制度改革探讨

在同一社会制度下并存不同的养老保险制度，这不利于社会的稳定，不利于机关事业单位用人制度的改革，不利于社会保障整体功能的发挥，也不利于市场经济的发展。因此，改革机关事业单位养老保险制度，建立统一的城镇职工养老保险制度，是完善社会主义市场经济体制的迫切要求。     

A rational,economic model of paygo tax rates

We argue that paygo rates are determined by a representative agent and a benevolent government jointly maximizing the expected life-time utility of the agent. The distributions of labor and capital income are calculated from national data on real GDP, real wages and the real return to capital since 1950. With uniform risk aversion, predicted rates explain 83% of the variance of observed rates. The globalization of capital markets would lead to convergence of paygo rates. Our results are immune to crises like 2008.     

A life cycle analysis of social security

Summary We develop an applied general equilibrium model to examine the optimal social security replacement rate and the welfare benefits associated with it. Our setup consists of overlapping generations of 65-period lived individuals facing mortality risk and individual income risk. Private credit markets, including markets for private annuities, are closed by assumption. Unlike previous analyses, we find that an unfunded social security system may well enhance economic welfare. In our benchmark economy, the optimal social security replacement rate is 30%, and an empirically more plausible replacement rate of 60% raises welfare compared with an economy with no social security system.We would like to thank Andy Atkeson, V. V. Chari, Steve Davis, Paul Evans, Lars Hansen, Tim Kehoe, Nobu Kiyotaki, Ed Prescott, José-Victor Ríos-Rull, Richard Rogerson, Tom Sargent, Nancy Stokey, Dick Sweeney, Robert Townsend, and the participants of the NBER Economic Fluctuations Small Group Workshop on Micro and Macro Perspectives on the Aggregate Labor Market in Palo Alto, the NBER General Equilibrium Theory Conference in Minneapolis, the Money and Banking Workshop at the University of Chicago, and the NBER Summer Institute. An earlier version of this paper was titled A Dynamic Stochastic General Equilibrium Analysis of Social Security. This material is based upon work supported by the National Science Foundation under Grant No. SES-9210291. We also thank the Minnesota and San Diego Supercomputer Centers for their support.     

农村社会保障体系建设中存在的问题及建议

农村社会保障体系是我国社会保障全系的重要内容。建立健全农村社会保障体系,对于解决“三农”问题,促进社会和谐稳定,全面建设小康社会具有重要意义。建立健全农村社会保障体系,应从我国国情出发,采取各种措施增加农民收入,增强农民的社会保障能力;把农业保险纳入农村社会保障体系;打破城乡二元社会保障结构,建立城乡一体化社会保障制度。     

Generalised Social Security Finance in a Two-Country World

This paper develops an overlapping generations model with generalised finance of social security in a two-country world. Social security finance includes a pay-as-you-go, a fully funded, and an optimal system as special cases. An increase in social security funding of country 1 increases capital, income and consumption per head in both countries. Also, it increases foreign assets in country 1 and foreign debt in country 2. The optimal level of social security funding is below the golden rule level. During adjustment an increase in funding has negative effects on country 1 and positive effects on country 2.     

Effect of social security on fertility and savings: an overlapping generations model

Old-age pension schemes do not exist in most developing countries, so adults bear children as security investments for the future. This phenomenon leads to unduly high rates of population growth. It has been hypothesized that introducing social security programs in such countries would increase savings rates and reduce the number of children born over the long term. The author studies the general equilibrium effects of some social security programs on rates of population growth and capital accumulation within an overlapping generations framework with endogenous fertility and savings. Specifically, Raul's overlapping generations growth model is extended to study the general equilibrium effects of payroll-tax-financed and child-tax-financed social security programs. It is shown that if the rate of intergenerational income transfers from young to old or child care cost is low, competitive equilibrium leads toward overpopulation and capital accumulation in a modified Pareto optimal sense; a social security program in such a case is therefore Pareto improving. A fully-funded system is not neutral when financed by child taxes. Finally, it is also shown that unlike in the case of exogenous fertility where competitive equilibrium attains steady state only asymptotically, fertility, when endogenous, may attain a unique globally steady state in finite time.     

全国社会保障基金股票投资组合绩效评价研究

股票投资作为社保投资中风险最大的投资产品,收益的高低直接影响社保基金整体的安全性。通过对社保基金股票投资组合总体绩效的研究发现,各投资组合在投资中均获得了超额收益。对社保基金股票投资组合的整体持续性检验结果表明,我国社保基金各投资组合的业绩并不具有持续性,反而具有反转型的特点;而分阶段持续性检验结果表明,在市场波动性较大的情况下,社保基金业绩没有表现出持续性,在市场相对稳定的情况下,社保基金业绩呈现出持续性的特点。     

社会保障财政风险与危机管理战略

我国正处于各种风险的频发期,给社会保障带来的影响不断加深,政府社会保障管理的难度也在不断扩大。在社会保障的常规性管理中贯穿风险意识、忧患意识、可持续发展意识,建立社会保障财政危机管理的核心价值观,是引领社会保障管理走向理性化、科学化的必要之路。以中国国情作为研究背景,探讨应对各种社会经济风险、自然灾害下的社会保障功能与政府职能问题,也从长期发展考虑,研究社会保障的战略发展模式,促使社会保障事业健康地发展。