The Research Of Urban Population Density Affects Firms Productivity Of Development Zone

The interactive development of urban and Development Zone is an important feature of China's regional economic development.Most of the existing literatures focus on one aspect of this interactive pattern that how does the establishment and development of Development Zones affect the growth of urban areas.Different from these literatures,this paper focuses on how urban population density affects the firms' productivity of Development Zone.On the basis of the spread-backwash theory included the idea of new economic geography,we propose a hypothesis that the impact of urban population density on firm's productivity of Development Zones is U trend.Using firm's panel data of China National Economic and Technical Development Zone during 2003-2007,our empirical results confirm this hypothesis well.When urban population density is less than 8145 people per km2,the backwash effect of urban exceeds the spread effect,and it shows that urban areas and Development Zone is a competitive relationship.Urban population density has a negative effect on the firm's productivity of Development Zone.When urban population density exceeds 8145 people per km2,the spread effect exceeds the backwash effect,and the relationship between urban areas and Development zone converts to cooperation,urban population density has a positive effect on the firm's productivity of Development Zone.Further results show that the urban spread-backwash effects not exist in technologicalintensive industries and in big firms.To obtain this spillover effect,a new firm at least need to spend 3 years to learn after it enters Development Zone.The conclusion of this paper shows that the coordination development between urban and development zone depends on urban population density.This is of great significance to the promotion of urbanization in various regions in formulating regional development policies.