The effect of the demographic change on inequality and the role of the pension system:Evidence from social security data and a dynamic structural life-cycle model

人口结构的变化给发达国家的社会带来了许多挑战。特别是，寿命的延长和相关的社会老龄化影响到福利国家的组织和筹资。因此，大多数政府已经引入或即将设计福利国家的改革，其中最重要的是养老金制度。与此同时，寿命的增加对社会的不平等产生了重要的分配效应和后果。首先，有明确的证据表明，预期寿命和寿命的增加在个人之间存在很大差异，并且与健康，收入，教育，工作历史和职业等有关。因此，虽然有些人将享受更长的寿命，并可能能够延长他们的工作寿命，以积累更多的终身收入或财富，但其他人并没有从这一总体趋势中受益，或者经历更长的健康状况不佳时期。第二，劳动力市场的影响和养老金改革的分配后果与人口结构的变化有关，在个人之间存在很大差异。一些人可以很容易地调整他们的就业行为或增加老年储蓄，作为对这些改革的回应。相比之下，其他个人可能难以延长工作年限，或者在积累更多私人储蓄方面可能面临限制。对这些人来说，退休年龄的提高可能会对就业产生负面影响，导致失业时间延长，从而导致净收入和养老金大幅减少。本课题的目的是研究寿命延长和与寿命延长相关的养老金改革对收入不平等和福利的影响，并根据这些结果讨论养老金制度最佳设计的意义。 更详细地说，我们结合联合收割机的证据，从社会保障数据和纵向家庭调查数据，研究异质预期寿命，养老金改革和收入不平等之间的相互作用。在该项目的中心，我们开发了一个结构模型的劳动力供应，退休和储蓄与异质预期寿命，允许研究寿命增加对不平等的后果，并分析各种养老金改革的财政和分配效果。我们补充了结构分析与新的描述性证据之间的预期寿命的异质性增加，以及这种增加是如何与特定的队列收入不平等的增加。此外，我们提供的因果关系证据的异质性影响的养老金改革，我们分析如何企业和职业的具体特点，以及个人和家庭变量影响个人的反应，养老金改革。

The demographic change poses numerous challenges to societies in developed countries. In particular, the increasing longevity and the related ageing of societies affect the organization and the financing of the welfare state. Therefore, most governments have introduced or are about to design reforms of the welfare state, most important of the pension system. At the same time the increasing longevity has important distributional effects and consequences for the inequality of a society. First, there exists clear evidence that life expectancy and the increase in longevity strongly differs between individuals and is related amongst others to health, income, education, working history and occupations. Therefore, while some individuals will enjoy a longer life and might be able to extend their working life to accumulate more lifetime income or wealth, other individuals do not benefit from this overall trend or experience longer periods in bad health. Second, the labor market effects and the distributional consequences of pension reforms related to the demographic change, strongly differ between individuals. Some individuals can easily adjust their employment behavior or increase old age savings as a response to these reforms. In contrast other individuals might have problems to extend their working life or might face constraints to accumulate additional private savings. For these individuals, the increase in retirement age might lead to negative employment effects and longer periods of unemployment and thus to a sizable reduction of net income and pensions. It is the objective of this project to study the effect of the increase in longevity and of pension reforms related to increasing longevity on income inequality and welfare and based on these results we will discuss implications for the optimal design of the pension system. In more detail, we combine evidence from social security data with longitudinal household survey data to study the interplay between heterogeneous life expectancy, pension reforms and income inequality. In the center of the project we develop a structural model of labor supply, retirement and savings with heterogeneous life expectancy that allows to study the consequences of increasing longevity on inequality and to analyze the fiscal and distributional effects of various pension reforms. We complement the structural analysis with new descriptive evidence about the increase in the heterogeneity in life expectancy between cohorts and how this increase is related to the cohort specific increase in income inequality. Moreover, we provide causal evidence about the heterogeneous effects of pension reforms; we analyze how firm- and occupation-specific characteristics as well as individual and household variables affect individual responses to pension reforms.