经济增长与收入分配差距：基于消费者异质性的动态一般均衡模型

The relation between long-term economic growth and income inequality has long been an important macroeconomic question for both economists and policy makers. Before China's economic reform in the 1970s, the household's income and living condition were highly equalized. This equalization led to a low level of economic efficiency and therefore a slow economic growth. Since 1978 and as the reform process becomes deepened, China's aggregate economic experiences a long period of fast growth and a great improvement in the efficiency. However, the income inequality among households, at the same time, is also larger. And this issue becomes more and more severe as evidence shown in various measurements of inequality and as shown by its adverse effects on different economic aspects. In Xi Jinping's report at the 19th National Congress of the Communist Party of China (CPC), he emphases that CPC and Chinese government must put the people’s interests above all else, see that the gains of reform and development benefit all our people in a fair way, and strive to achieve shared prosperity for everyone. And Xi also emphazes that CPC and Chinese government will work to see that individual incomes grow in step with economic development and to narrow the income gaps. This proposal is intended to study the relation between economic growth and income disparity in a mainstream theoretical macroeconomic framework. We will study an economy with a population of heterogeneous consumers and build a dynamic general equilibrium model to address our research question. We will start from the micro foundation of the macro question, i.e. optimization problems，and then construct a general equilibrium model. We investigate the role of redistributional policy, such as progressive taxation, in answering our research question. The model also captures some interesting interactions between the factor market, such as labor market, and the output market. These two markets jointly determine the general equilibrium in the model. Our preliminary results show that if a unique steady state exists, elastic or inelastic labor supply, the curvature of marginal tax function and the curvature of marginal rate of substitution are three keys to answer our proposed question. For example, with inelastic labor supply, a more dispersed population will have a lower steady state, but a higher level of aggregate labor supply and a higher level of aggregate output. On the individual level, the consumer's income and consumption are therefore higher in such an economy. If labor supply is elastic, the compositions of aggregate labor supply as well as the individual labor supply matter. In this project, we will try to disentangle the knot of all these elements and try to see how each factor affects the individual and aggregate levels of the economic variables. We will derive the analytical results for these.

经济增长和收入差距的关系一直是经济学者和政策制定者高度关注的一个宏观经济问题，具有重要的理论和现实意义。改革开放以前，中国平均主义盛行，这种分配倾向伴随的是经济效率低下，经济增长缓慢。随着经济体制改革深化，人均收入和国民生产总值实现了大幅提高，同时收入差距也在不断扩大。习总书记十九大报告指出，让改革发挥成果更多更公平惠及全体人民，朝着实现全体人民共同富裕不断迈进，并强调坚持在经济增长的同时要缩小收入分配差距。本课题就拟在宏观经济理论框架下，从异质性消费者决策的微观基础出发，构建动态一般均衡模型以研究经济增长和收入差距之间的关系，并试图探究再分配政策，如个人所得税，在这个关系决定中的作用，以及劳动力市场和产品市场均衡之间的互动关系。前期相关研究显示，一国经济增长和收入差距之间的关系可能与个人所得税边际税率的凹凸性、劳动与消费的替代是否存在收入效应以及个体劳动供给函数的凹凸性有关系。

经济增长和收入差距的关系一直是经济学者和政策制定者高度关注的一个宏观经济问题， 具有重要的理论和现实意义。改革开放以前，中国平均主义盛行，这种分配倾向伴随的是经济效率低下，经济增长缓慢。随着经济体制改革深化，人均收入和国民生产总值实现了大幅提高 ，同时收入差距也在不断扩大。习近平总书记在十九大报告中指出，让改革发挥成果更多更公平惠及全体人民，朝着实现全体人民共同富裕不断迈进，并强调坚持在经济增长的同时要缩小收入分配差距。本课题主要从异质性消费者决策的微观基础出发，构建动态一 般均衡模型，从理论上研究经济增长和收入差距之间的关系，并试图探究再分配政策，如个人所得税， 在这个关系决定中所起的作用。项目主要考察了两个维度的消费者异质性，即主观贴现率和个体劳动效率的异质性；通过考察劳动力市场和产品市场均衡之间的互动关系，得到不依赖与具体函数形式的较为一般性的结论。我们发现一国经济增长和收入分配之间不存在一个确定的关系，这个关系同时受个人所得税边际税率的凹凸性、劳动与消费的替代是否存在收入效应以及个体劳动供给函数的凹凸性等三方面的共同影响。在对微观主体的决策变量和宏观经济均衡进行分析的基础上，我们对于文献中通常使用的函数形式和相关参数取值进行了进一步分析，我们从数量上对理论部分的一般性结论进行了验证。项目的科学意义就在于在不依赖于具体（效用、生产）函数形式的基础上，探索消费者异质性特征的分布对于经济增长和收入分配的影响，并找出其中的影响因素和机制。项目成果包括国际A类期刊论文1篇和省部级一等奖1项。