长三角一体化区域扩容的城市创新发展效应研究

城市合作推动的行政区经济转向一体化经济背景下,长三角一体化区域扩容在强化多城市合作、优化要素集散的同时,对城市创新发展产生何种效应?本文利用1990—2017年长三角城市面板数据,将长江三角洲城市经济协调会扩容作为准自然实验、基于双重差分模型,评估一体化区域扩容的创新发展效应。在此基础上,采用中介模型、空间计量模型等方法,探讨一体化区域扩容影响创新发展的机制。结果表明：加入协调会能够显著促进城市创新发展,经多重稳健性检验的验证依然成立;空间扩容的创新发展效应存在多重异质性,呈现为城市规模上的“马太效应”,动态效应上的“U型”演变态势,不同批次上的“倒U型”差异,不同区域上的安徽最大、江苏其次、浙江不显著的差异。驱动机制分析发现,加入协调会带来的市场一体化深化、要素集聚水平提升、创新联系强化等,是推动城市创新发展的重要机制,而空间溢出效应、创新联系的区域差异,是城市创新发展效应异质性的重要因素。未来,积极融入城市群是城市创新发展重要路径之一,但重点在于深化城市间创新合作,同时政府也要加强对一体化发展可能负面效应的关注。

The effects of integration regional enlargement on urban innovation developments in the Yangtze River Delta

With the emergence of the importance of urban agglomeration′s innovation status and innovation interaction across different cities, actively integrating into the urban agglomeration innovation network has become an important measure to realize the innovative development. In the context of the transformation of China′s administrative region economy to an integrated economy driven by urban cooperation, the integration regional enlargement in the Yangtze River Delta has strengthened multi-city cooperation and optimized the distribution of factors. What impacts does it have on urban innovation development? Based on the panel data of prefecture level from 1990 to 2017 in the Yangtze River Delta, this paper regards the enlargement of the Yangtze River Delta Urban Economic Coordination Committee as a quasi-natural experiment, and uses the difference-in-difference method to estimate the effects of integration regional enlargement on urban innovation development. On this basis, the mediation model and spatial econometric model are used to explore the mechanism of integration regional enlargement affecting innovation developments. The results show that integration regional enlargement has significantly promoted urban innovation, which is verified by multiple robustness tests. Further studies show that the innovation development effects of integration regional enlargement have multiple spatio-temporal heterogeneity. From the perspective of different city sizes, the effects show significant difference of "Matthew effect". From the perspective of dynamic effects, with the time of city joining the UECC increase, a "U-shaped" evolution trend emerges. From the perspective of different batches, the effect presents a significant "inverted U-shaped" differentiation pattern. From the perspective of different regions, Anhui province has the largest effect, followed by Jiangsu province, but Zhejiang province is not significant. Mechanism verifications show that integration regional enlargement in the Yangtze River Delta has promoted urban innovation development through the deepening of market integration, the improvement of factor concentration level and the strengthening of innovation connection. In this process, the regional differences of spatial spillover effects and innovation linkage are the important factors leading to the spatio-temporal heterogeneity of urban innovation development effects. To further promote urban innovation development, integrating into the urban agglomeration innovation network has become an important way for cities to achieve innovation development. However, the governments at all levels should pay more attention to the possible negative effects of integration regional development.