20世纪八九十年代，美国和欧洲地区出现了中等技能劳动就业比重不断下降、高技能劳动和低技能劳动就业比重不断上升的就业极化现象。以受教育年限和工资收入为技能划分标准下的就业结构分析均得出一致结果。就业极化现象导致的中等技能就业比重下降是美国2008年经济危机后就业复苏困难的重要原因。对中国而言，就业市场出现了“技工荒”和收入差距不断扩大现象。中国作为发展中国家，经济发展条件和发展阶段与欧美等发达国家存在很大差距，那么中国是否也存在了就业极化现象？“技工荒”和收入差距扩大是否与就业极化有关？就业极化的产生机制和其影响就业与收入不平等的过程是本书要回答的问题。

现有研究认为，美国和欧洲就业极化产生的主要原因是技能偏向型技术进步和国际贸易。在全球化背景下，发达国家和发展中国家就业市场均受到技能偏向型技术进步和国际贸易的影响，使得高技能劳动相对低技能劳动就业比重不断上升，工资不平等也不断扩大。然而已有研究表明，中国就业极化现象开始显现。由于中国与欧美发达国家的国情不同，就业极化产生的机制或许有所差异。因此，本书在已有的研究思路和方法基础上，对中国就业结构是否呈现就业极化特征进行验证，并分析中国就业极化产生的原因。本书认为，2008—2017年，中国出现了就业极化现象，技能偏向型技术进步、国际贸易和产业结构升级是中国就业极化产生的主要原因。

具体而言，本书第一章对中国是否存在就业极化现象进行特征事实验证。首先，从受教育水平、工资水平和工作任务三个角度对技能进行划分，对每种技能划分下的就业结构情况进行分析，观察不同产业、部门和细分行业在某些年份是否出现了就业极化特征；其次，从技能溢价变化情况对工资不平等进行分析。第二章分析技能偏向型技术进步影响就业极化的机制。第三章首先分析国际贸易影响就业极化的机制，其次结合中国国际贸易发展特征分析国际贸易对中国就业结构的影响。第四章从产业结构升级的角度分析就业极化产生的机制，并结合中国产业结构升级特征从就业弹性、就业偏离度和要素投入三个方面分析产业结构升级对中国就业结构的影响。最后一章提出有针对性的政策建议。本书的研究结论如下。

首先，中国在2008—2017年已经出现了就业极化现象。在受教育水平、平均工资和工作任务性质三种技能分类标准下，中国就业市场在2008—2017年呈现轻微的就业极化现象。对产业部门内部的技能结构变化分析发现，农业就业结构呈现就业升级特征，制造业内部呈现了就业极化特征，而服务业中多数低技术行业呈现就业升级特征，高技术行业呈现就业极化特征。

其次，技能偏向型技术进步通过常规化假设引起了中国就业极化现象。技能偏向型技术进步与技能劳动互补，与非技能劳动替代。随着技术的革命性发展，技术进步可以以更低的成本来完成中等技能劳动从事的重复性工作，从而对中等技能劳动产生了替代。对中国而言，随着新技术的应用和生产率的提升，中国企业对中等技能劳动的需求不断下降。另外，技能偏向型技术进步使得高技能劳动与中低技能劳动的生产率差距异扩大，技能溢价不断上升。

再次，国际贸易下的技术引进引起了中国技能偏向型技术进步，进而影响了各类技能劳动就业比重的变化。中国利用劳动密集型产品出口赚取的外汇来购买国外先进技术，这些技术的应用引起了中国技能偏向型技术进步。另外，软件服务业在离岸外包中的比重不断上升增加了中国高技能劳动需求。

最后，产业结构升级过程中过快增长的资本投入引起了中等技术行业的从业者就业下降。一方面，制造业的就业弹性较低，制造业中等技术行业的就业结构偏离度最大，制造业对就业的吸纳能力和带动作用最小；另一方面，制造业资本投入快速增长的同时，就业增速在放缓。因此，在产业结构从劳动密集型产业向资本密集型产业升级过程中，快速增长的资本投入对中等技术行业从业者产生了替代作用，促进了就业极化的形成。

降低就业极化对中国劳动力市场的影响，应从以下五个方面入手：第一，加快提升高等教育质量和职业教育培训质量，提升整体高中低技能劳动生产率，并扩大各类技能劳动供给；第二，利用国内巨大市场需求积极引进国外先进技术和人才，加快中国技术进步进程；第三，加快产业结构升级，优化劳动力结构，让各类技能劳动配置在生产率各异的行业中；第四，加快户籍制度和社会保障制度改革，消除各类技能在不同部门和地区间自由流动的限制；第五，完善社会保障制度，通过转移支付、税收和福利制度来缩小技能和非技能劳动工资差距。

关键词：就业极化；工资不平等；技能偏向型技术进步；常规化假设；国际贸易；产业结构升级

Abstract

In the 1980s and 1990s,the polarization of employment emerged in the United States and Europe,where the employment proportion of medium-skilled labors continued to decline,and the empolyment proportion of high-skilled and low-skilled labors and increased.The results of employment structure analyses based on the educational level and wage income are the same.The decline of the empolyment proportion of medium-skilled labors caused by the polarization of employment is an important reason for the difficulty of employment recovery after the 2008 economic crisis in the United States.For China,there is a shortage of“technical workers”and a widening income gap in the employment market.As a developing country,China's economic development conditions and development stages are very different from those of developed countries such as Europe and the United States.Does China also have employment polarization?Is the employment polarization related to the“technical shortage”and the widening income gap?The mechanism of employment polarization and its process of affecting employment and income inequality are the questions answered in this book.

Existing researches suggest that the polarization of employment polarization in the United States and Europe is mainly due to the skill-biased technological advancement and international trade.In the context of globalization,the employment markets in developed and developing countries are affected by skill-biased technological advancement and international trade,which make the employment proportion of high-skilled labors relatively low-skilled labors rise and wage inequality continue to expand.However,studies have shown that the polarization of employment in China is beginning to emerge.Due to the differences in national conditions between China and developed countries such as Eu rope and the United States,the mechanism of employment polarization may be different.Therefore,based on the existing research ideas and methods,this book verifies whether the employment structure of China shows employment polarization characteristics,and analyzes the reasons for the polarization of employment in China.This book argues that between 2008 and 2017,China experienced the ehenomenon of employment polarization.Skill-biased technological advancement,international trade and industrial structural upgrading are the main reasons for employment polarization in China.

Specifically,the first chapter of this book verifies the existence of the phenomenon of employment polarization in China.The first chapter first divides the skills from the three levels of education,wages and work tasks,analyzes the employment structure under each skill division,and observes whether employment polarization has appeared in different industries,departments and sub-sectors in some years.Characteristics and analysis of wage inequality from changes in real wages and skill premiums.The second chapter analyzes the mechanism of skill-biased technological advancement affecting employment polarization.The third chapter first analyzes the mechanism of international trade affecting employment polarization,and then analyzes the impact of international trade on China's employment structure based on the characteristics of China's international trade development.The fourth chapter analyzes the mechanism of employment polarization from the perspective of industrial structural upgrading,and analyzes the impact of industrial structural upgrading on China's employment structure from three aspects: employment elasticity,employment deviation and factor input.The last chapter proposes targeted policy recommendations.The conclusions of this book are as follows.

First,China has seen the phenomenon of employment polarization in 2008—2017.Under the three skill classification criteria of education level,average salary and job task,the Chinese job market showed a slight employment polarization in 2008—2017.The analysis of the changes in skill structure within the industrial sector finds that the agricultural employment structure shows employment upgrading characteristics,and the manufacturing industry shows employment polarization characteristics.Most of the low-tech industries in the service industry shows employment upgrading characteristics,and the high-tech industries shows employment polarization characteristics.

Secondly,the skill-biased technological advancement has caused the polarization of employment in China through routinization hypothesis.Skill-biased technological advancement complements the skilled labors and substitutes the non-skilled labors.With the revolutionary development of technology,technological advancement can complete the repetitive work of medium-skilled labors at a lower cost,thus replacing the medium-skilled labors.For China,as new technologies are applied and productivity is increasing,the demand for medium-skilled labor in Chinese companies is declining.In addition,skill-biased technological advances have widened the productivity gap between high-skilled labor and low-skilled labor,and the skill premium has continued to rise.

Third,the introduction of technology through international trade has caused China's skill-biased technological advancement,which in turn has affected the employment proportion of various types of skills.China uses foreign exchange earned from the export of labor-intensive products to purchase advanced foreign technology.The application of these technologies has caused China's skill-biased technological advancement.In addition,the increasing proportion of software services in offshore outsourcing has increased China's demand for highly skilled labors.

Fourth,the excessive capital investment in the process of upgrading the industrial structure has caused the employment of practitioners in the middle-tech industries to decline.On the one hand,the employment elasticity of the manufacturing industry is relatively low,the employment structure of the medium-tech industries in the manufacturing industry is the most deviated,and the manufacturing industry has the least absorption capacity and the driving effect;on the other hand,while the manufacturing capital investment is growing rapidly,employment growth is slowing.Therefore,in the process of upgrading the industrial structure from labor-intensive industries to capital-intensive industries,rapidly rising capital investment has played a substitution role for practitioners in the middle-tech industries and promoted the formation of employment polarization.

To reduce the impact of employment polarization on China's labor market,we should start from the following five aspects:First,accelerating the improvement of the quality of higher education and the quality of vocational education and training,improving the overall high,medium and low-skilled labors productivity,and expanding the supply of various types of skills; Second,We will use the domestic market demand to actively introduce foreign advanced technology and talents to accelerate the progress of China's technological progress; Third,accelerating the upgrading of industrial structure,optimizing the labor structure,and allowing all kinds of skilled labor to be deployed in industries with different productivity; Fourth,accelerating the reform of the household registration system,and eliminating the restrictions on the free flow of various skills among different departments and regions; Fifth,improving the social security system and reducing the wage gap between the skills and non-skilled labors through transfer payment,taxation and welfare systems.

Keywords: employment polarization; wage inequality; skill-biased technological progress; routinization hypothesis; international trade; industrial structural upgrading