人口结构转型、人口红利演进与出口增长——来自中国城市层面的经验证据

Demographic Structure Transition, Demographic Dividend Evolution and Export Growth: Evidence from Chinese City-level Data

本文基于2000年、2005年和2010年三次全国人口普查数据,构建城市层面包含人口流动信息的人口结构指标,从微观层面研究人口结构变动对出口的影响及其作用机制。研究发现,以劳动人口比或抚养比为表征的城市人口结构变动会显著影响出口,城市劳动人口比的提升或城市抚养比的下降会显著促进出口。对影响机制的实证检验表明,城市人口结构变动对出口的影响会伴随用工成本的上升而逐渐弱化,即存在人口结构变动影响出口的“成本效应”。城市人口结构变动对出口的影响会伴随人力资本水平的提升而逐渐弱化,即存在人口结构变动影响出口的“人力资本效应”。城市人口结构变动对出口的影响主要源于对劳动力投入的依赖性。本文的研究结论意味着,促进人力资本提升,加快实现“人口红利”向“人才红利”的转变,是应对人口老龄化背景下中国出口转型升级的重要思路。

Since China's reform and opening up, demographics have played an important role in the development of China's overseas trade. The huge population provides an abundant and cheap labor force for Chinese firms and also lays a solid foundation for the successful implementation of the export-oriented economic development strategy. Since the start of the 21 st century, however, China's demographic structure has been undergoing profound changes. On the one hand, the demographic dividend is gradually disappearing, and the problems of population aging and labor shortage have become more prominent. On the other hand, with the gradual easing of the household registration system (Hukou system), the domestic population flow has become more frequent. Since the 1980s, more than 340 million people in China have migrated;that is the largest population migration in human history. Amid a shifting demographic structure and the increasing frequency of population migration, it is important to study the impact of structural demographic changes on exports and its mechanism from a micro perspective. Doing so can not only highlight the necessity of focusing on the “talent dividend” rather than the “demographic dividend”, but also help clarify how to transform and upgrade China's overseas trade. Using data from the three national censuses in 2000, 2005, and 2010 and highly detailed firm export information provided by the Customs Database, this paper constructs a demographic structure indicator that includes population migration information at the city level and studies the effect of demographic structure changes on firm exports. The results indicate that an increase in the labor-population ratio or a decline in the dependency ratio will significantly promote exports, a result that holds under a multi-dimensional robustness test. The impact of city demographic structure on exports will gradually weaken with the increase of labor costs and human capital level;that is, there are cost-and human capital-related effects of demographic structure changes on exports. Further analysis shows that the impact of city demographic structures on exports is mainly due to the dependence on labor input. To solve the potential endogeneity problem in the empirical estimation, this paper first adopts a more exogenous explanatory variable, namely the demographic structure. In addition, by using highly detailed panel data (firm-product-destination-trade mode-year), potential reverse causality problems are avoided. Third, this paper constructs high-dimensional panel data for firm-product-destination-trade mode-year, which greatly reduces the biases caused by omitted variables through strict fixed effect control. Fourth, multiple demographic indicators, such as the city-level dependency ratio, are constructed to deal with the measurement error problem. Fifth, the data dimensions are scaled and the benchmark results are verified repeatedly across multiple dimensions. Sixth, using historical variables as instrumental variables for regression, the credibility of the benchmark results is further verified. This paper contributes to the literature in several ways. First, it builds a demographic structure index based on population migration information at the city level, which enables micro-level analysis of the relationship between demographic structures and exports. Second, this paper identifies cost and human capital mechanisms in the effect of demographic structures on exports from a micro perspective. Compared to the existing theoretical analysis framework, which is based on the saving rate mechanism, these mechanisms are important supplement. Third, the conclusions of this paper not only provide empirical evidence for the necessity of accelerating from a “demographic dividend” focus to a “talent dividend” focus in China, but also help to explain the current “talent war” between cities. It provides empirical evidence for promoting the reform of the current household registration system and realizing the rational flow of labor.