中国城市化进程的“S”型演变及政策效应评价——基于Logistic模型的实证研究

Law about “ S” Type Evolution of Urbanization and the Policy Shock Effect: One Empirical Analysis Based on the Logistic Model

基于Logistic模型,并利用相关城市化数据,本文对我国城市化进程与饱和水平S、初始水平a和速度指标b的内在关系以及城市化进程"S"型演变的影响因素进行了实证研究。结果表明:(1)城市化的饱和水平S确定了城市化进程的上限,城市化的初始水平a和速度指标b的大小则决定了城市化进程的实现周期;(2)城市化进程的"S"型趋势受到政策变革的干扰,并通过影响速度指标b的大小引致城市化进程的加速或者停滞过程;(3)城市化本质上可视作一个多维度的系统演变过程,主要包括了时间维度、空间维度和城市化系统本身。

Based on the Logistic model and the relevant urbanization data, this paper makes an empirical study on the intrinsic relationship between the urbanization process and the saturation level S, the initial level a and the velocity index b and the influencing factors of the urbanization process. The results show that： （1） the saturation level of urbanization S determines the upper limit of the urbanization process, the initial level of urbanization a and the size of the speed index b determine the realization of the urbanization process cycle; （2） the ＂S＂ type of urbanization process is disturbed by policy change and the acceleration or stagnation process of urbanization process is affected by the size of speed index b; （3） Urbanization can be regarded as a multidimensional system evolution process, which mainly includes the time of the process of urbanization and is caused by the change of the policy, dimension, spatial dimension and urbanization system itself.