信息网络基础设施建设能驱动城市创新水平提升吗?——基于“宽带中国”战略试点的准自然试验

Can the construction of information network infrastructure drive the level of urban innovation?A quasi-natural experiment of“Broadband China”pilot policy

作为现代化经济体系空间网络的"中枢节点"和"传输纽带",信息网络基础设施建设对激发城市创新动力、构建数字网络强国具有重要意义。基于2011—2018年地级市面板数据,以"宽带中国"战略试点为准自然试验,采用双重差分法评估信息网络基础设施建设的创新驱动效应。研究发现:"宽带中国"战略试点政策显著促进了城市创新水平提升,该结论在采用工具变量和倾向得分匹配等一系列稳健性检验后仍然成立。从时空效应来看:试点政策的创新驱动效应具有动态可持续性,随着年份的推移,效果不断增大;且试点政策加速推动了地理相邻城市的信息和创新要素流动,产生了较强的示范效应,并加剧了示范城市建设的政策洼地效应,对经济相似地区创新资源和要素产生了一定的虹吸效应。从影响机制来看,试点政策通过集聚驱动效应、结构优化效应促进城市创新,数字金融助推效应相对较小。从异质性来看,试点政策对东部地区城市和行政等级较高的直辖市、省会及副省级等城市的创新驱动效应相对更强。研究结论为深入推进新型基础设施建设、加快推动创新型国家建设提供了参考和借鉴。

As information network infrastructure acts as the"central node"and"transmission link"of the modern economic system’s spatial network,construction of such infrastructure is of great significance in stimulating urban innovation and building digital network power.Based on the panel data of prefecture-level cities from 2011 to 2018,this paper takes the"Broadband China"pilot policy as a quasi-natural experiment,and uses a difference-in-differences model to evaluate the innovation-driven effect of information network infrastructure construction.The study finds that the"Broadband China"pilot policy significantly promotes the improvement of urban innovation.This conclusion is significantly established after a series of robust tests,including instrumental variables and propensity score matching.From the perspective of time and space effect,the innovation-driven effect of pilot policies has dynamic sustainability,which increases over time.Moreover,pilot policies accelerate the flow of information and innovative elements in geographically adjacent cities,produce a strong demonstration effect,intensify the low-land policy effect of demonstration city construction,and produce a certain siphon effect on innovative resources and elements in economically similar areas.From the perspective of influence mechanism,pilot policies promote urban innovation through agglomeration-driving effect and structure-optimization effect,whereas the boosting effect of digital finance is relatively small.From the perspective of heterogeneity,pilot policies have a stronger innovation-driven effect on the eastern region,on municipalities directly under the central government with higher administrative levels,on provincial capitals,and on sub-provincial cities.This paper’s conclusion provides a reference for further promoting the construction of new infrastructure and accelerating the construction of an innovative country.