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，社会寿命的延长和相关的老龄化影响了福利国家的组织和融资。因此，大多数政府已经或即将实施福利国家改革，其中最重要的是养老金制度。与此同时，寿命的延长对社会的不平等具有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，而且与健康、收入、教育、工作经历和职业等因素有关。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，但其他人并不能从这一整体趋势中受益，或者经历更长的健康状况不佳的时期。其次，与人口变化相关的养老金改革的劳动力市场效应和分配后果在个体之间存在很大差异。作为对这些改革的回应，一些个人可以很容易地调整他们的就业行为或增加老年储蓄。相比之下，其他人可能在延长工作寿命方面遇到问题，或者可能面临积累额外私人储蓄的限制。对这些人来说，提高退休年龄可能导致负面的就业影响和更长的失业期，从而导致净收入和养恤金的大幅减少。该项目的目标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，并基于这些结果，我们将讨论对养老金制度优化设计的影响。更详细地说，我们将社会保障数据的证据与纵向家庭调查数据结合起来，研究异质性预期寿命、养老金改革和收入不平等之间的相互作用。在项目的中心，我们开发了一个具有异质预期寿命的劳动力供给、退休和储蓄的结构模型，该模型允许研究寿命延长对不平等的影响，并分析各种养老金改革的财政和分配影响。我们用新的描述性证据来补充结构分析，这些证据证明了群体之间预期寿命异质性的增加，以及这种增加与群体特定的收入不平等增加之间的关系。此外，我们还提供了养老金改革异质性效应的因果证据；我们分析了企业和职业特征以及个人和家庭变量如何影响个人对养老金改革的反应。

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.