Industrial Diversification?Economy Density And Urban Innovation Capability

At present,innovation has gradually become the core driving force for the development of a country and a region,and innovation capability has increasingly become an important symbol of urban comprehensive competitiveness.The externalities and knowledge spillovers brought by Jacobs' industrial diversity agglomeration to urban innovation are increasingly valued by the academic community.With the continuous deepening research on the relationship between diversity agglomeration and innovation,on the one hand,the evolutionary economic geologist K.Frenken further distinguished industrial diversity into related variety and unrelated variety from the perspective of knowledge cognitive distance.It is believed that knowledge spillovers will only exist between related and complementary industries,because they have similar knowledge base,while unrelated variety is considered to reflect the “investment portfolio effect” to avoid industry risks.On the other hand,people are the foundation of innovation,and face-to-face communication between people is an important way to promote knowledge spillovers.Therefore,in the era of agglomeration economies where global innovation resources and factors are constantly gathering and gaps in regional innovation capabilities are widening,it is necessary to explore the influence of industrial diversity and the economic density represented by the agglomeration degree of employment population and economic output on urban innovation capabilities.Based on the related theories and research progress of industrial agglomeration,economic density and innovation,this paper takes 41 cities above the prefecture level in the Yangtze River Delta Region as the research object.Firstly,industrial diversity is divided into related variety and unrelated variety,and the urban economic density is synthetically measured with output density and employment density.Then,using the methods of entropy index measure,coefficient of variation and other methods to measure the urban industrial diversity,economic density and innovation ability,and analyze their development status,evolution characteristics and causes.Finally,using Stata tool to build a measurement research model,focusing on the empirical analysis of the impact of industrial diversity on city innovation capability,economic density on city innovation capability,and industrial diversity and economic density,which together affect city innovation capability.The study found that:(1)During the period of the survey,the index of industrial diversity among the cities of the Yangtze River Delta region differed significantly.Cities with higher related variety index were mainly distributed in the more economically developed areas around the Taihu Lake and coastal areas,while the cities with higher unrelated variety index are mainly distributed in areas with relatively weak economic foundations such as Anhui Province,western Jiangsu Province and southwestern Zhejiang Province.(2)The economic density in the Yangtze River Delta region shows a steady rising trend year by year,and the distribution characteristics of employment density and output density are basically the same,and the Taihu Lake area is a zone of high economic density and attenuated to peripheral cities.(3)Compared with the economic strength gap,the gap in innovation capability among cities in the Yangtze River Delta region is greater,and the innovation results are highly concentrated in a few cities such as Suzhou,Ningbo and Shanghai.However,the concentration of innovation results in the period of investigation showed an overall trend of shrinking year by year.(4)Industrial diversity will bring a significant promotion to innovation capability.After distinguishing industrial diversity into related variety and unrelated variety,it was found that the related variety has a significant effect on the improvement of city innovation capability.In contrast,the portfolio effect brought by unrelated variety is only verified in large city sample groups.(5)The output density has a direct effect on the city's innovation ability.Compared with small and medium-sized cities,its promotion effect on big cities is more obvious,and employment density has no direct promotion effect on the improvement of city innovation ability.(6)The interaction between output density and industrial diversity has no obvious impact on city innovation ability.Employment density can influence the effect of knowledge spillover through interaction with industrial diversity,indirectly promote the improvement of city innovation capability,and the interaction between employment density and related variety has a greater impact on city innovation ability.