中国城市化发展中的规模逆梯度现象研究——理论分析与实证检验

The Scale Inverse Gradient in the Urbanization of China——Theoretical Analysis and Empirical Testing

城市化发展中城市规模与净集聚效应呈现倒U型关系,当城市规模过度扩张时,规模逆梯度现象就会出现。本文从理论和实证两个层面对中国城市化发展中的规模逆梯度现象进行研究。首先,通过构建静态一般均衡模型,求解出最优城市化率,从理论上论证了城市规模逆梯度现象的存在。其次,使用2006-2016年中国统计年鉴中的历史数据,引入环保型投入要素的DEA-Malmquist对中国31个省会级城市的综合发展效率进行测算。结果表明,规模较小城市中,"规模效率"能够有效促进城市"综合发展效率"的提升,但规模较大城市则呈现出"综合发展效率"主要通过"纯技术效率"这一渠道来提升而非单纯依靠"规模效率"来提升的特点。与此同时,本文的实证研究更进一步验证了中国城市发展的进程中存在着"规模逆梯度现象",未来城市经济发展过程中,不仅要注重规模的扩大,还需提升内在效率。

The relationship between urban scale and net agglomeration in urbanization is inversely U-shaped. When the urban scale expands excessively, the phenomenon of inverse gradient of scale will appear. This paper analyses this phenomenon in the development of urbanization in China from the theoretical and empirical perspectives. By constructing a general static equilibrium model, the optimal urbanization rate level is solved, and the existence of the inverse gradient phenomenon of urban scale is theoretically demonstrated. Using China Statistical Yearbook data from 2006 to 2016, we measure 31 cities- comprehensive efficiency of urban development by introducing the envi- ronmental protection input factor to expand the traditional DEA-Malmquist Index method. The em- pirical testing results show that in the development of smaller cities, ＂Scale efficiency＂ effectively promotes the ＂Comprehensive urban development efficiency＂. But in the larger cities, ＂Comprehen- sive development efficiency＂ comes mainly from ＂Pure technical efficiency＂ which reflects the efficiency of resource allocation, rather than just ＂Scale efficiency＂. The empirical study further verifies the expianatory power of the theory to the real world.