Abstract: Market segmentation in China has always been an important issue of concern in academic circles.Eliminating market segmentation and promoting the construction of a unified domestic market is of great strategic significance for enhancing the ability of independent innovation and building a new development pattern,and the practice and experience of promoting the regional market integration construction can provide strong support for the construction of a large,unified national market.“County-to-district Conversion (CTDC)” breaks down the administrative barriers between the municipal district and the merged county,helps to reduce the market segmentation between districts and counties and promote the free flow of elements and the development of regional market integration,which objectively provides a good quasi-natural experiment for this paper to study the impact of regional market integration on urban technological innovation.
Based on the balanced panel data of 275 cities in mainland China from 2007 to 2019,with the help of the regional market integration policy of CTDC,this paper adopts the multi-period DID method to investigate the impact of regional market integration on urban technological innovation,and makes contributions in the following three aspects:First,it expands the research perspective.Innovation is an important driving force to promote economic growth and improve the efficiency of green economy.This paper directly studies the impact of regional market integration on urban technological innovation,which is helpful to clarify the micro-mechanism between regional market integration and other economic effects.Second,it explores the impact mechanism.Government investment in science and education can provide financial support for basic research and enterprise R&D.Based on the theory of “demand-induced innovation”,this study selects government expenditure on science and education and residents' consumption level as intermediary variables to test the mechanism of regional market integration affecting technological innovation from both sides of supply and demand.Third,it studies the heterogeneity.According to the differences in urban location,science and education level,administrative level and market integration degree,this paper analyzes the heterogeneity of the technological innovation effect of regional market integration,and further studies the spatial characteristics of CTDC policies and the regulating effects of urban population density,size and marketization level.
The research conclusions of this paper are as follows:(1)CTDC significantly promotes urban technological innovation,and a series of robustness test results still support this conclusion.Quantile estimation results show that the promotion effect increases gradually with the improvement of innovation level,and it is also found that CTDC promotes technological innovation by increasing government expenditure on science and education and residents' consumption level.(2)Heterogeneity test shows that the promoting effect of CTDC on technological innovation is the strongest in eastern cities,followed by central cities,and not significant in western cities.However,it has a significant inhibiting effect in northeastern cities.The effect of CTDC on technological innovation is stronger in cities with better science and education resources,key cities and sub-provincial cities.(3)The effect of CTDC on urban technological innovation inhibits inconspicuously when the distance between the merged county and city administrative center is within 20 kilometers,increases rapidly between 20 and 60 km,and weakens obviously more than 60 km.In addition,urban population density,size and marketization level can significantly enhance the role of CTDC in promoting technological innovation.
The findings of the study have the following policy implications.Firstly,governments should use the CTDC rationally to promote regional market integration,and play the role of regional market integration in promoting urban technological innovation.Cities in eastern and central China should continue to strengthen the connectivity of infrastructure between the merged county and the original municipal districts,further promote the free flow of various factors such as labor and capital,enhance the deep integration between district and county markets,deepen the degree of regional market integration,and play the role of CTDC in promoting technological innovation.Secondly,through the reform of CTDC,local governments should further optimize the structure of fiscal expenditure,increase the proportion of expenditures on education and science,and strengthen the supporting role of government expenditures on science and education for technological innovation.In the process of promoting regional market integration,it is necessary to pay attention to improving residents' consumption environment,raising residents' consumption willingness and level,guiding enterprises to carry out R&D according to the changes of consumer demand,and stimulating the “demand-induced innovation” effect.Finally,it is worth noting that CTDC may have a negative effect on urban technological innovation.Small and medium-sized cities and cities in northeast China should speed up market-oriented reform and enhance talent attraction,instead of simply adopting CTDC adjustment.In the future,local governments at all levels should prudently push forward the reform of CTDC according to their own conditions,and enhance its positive effect in breaking down regional market segmentation and promoting technological innovation.

Key words: Regional Market Integration, County-to-district Conversion, Urban Technological Innovation, Multi-phase DID

摘要： 本文基于2007—2019年中国275个城市的面板数据,采用多期双重差分法考察“撤县设区”这一区域市场一体化政策对城市技术创新的影响。研究发现,撤县设区显著促进城市技术创新并随着创新水平的提升而逐渐增强。机制检验表明,撤县设区通过提升政府科教支出和居民消费水平促进城市技术创新。异质性检验显示,撤县设区对技术创新的促进效应在东部城市的表现最强,中部城市次之,西部城市不显著,东北城市则具有显著的抑制作用,且撤县设区的创新效应在科教资源较好、重点城市和撤并多个县的城市表现更强。进一步的研究发现,撤县设区对城市技术创新的影响存在明显的空间差异特征,城市人口密度、城市规模和市场化水平对撤县设区的技术创新效应具有显著的正向调节作用。

关键词: 区域市场一体化, 撤县设区, 城市技术创新, 多期DID