创新型城市建设对绿色全要素生产率的影响

Impact of innovative city construction on green total factor productivity

在DEA框架下,基于考虑非期望产出的方向性距离函数,文章运用Global-Malmquist-Luenberger生产率指数测度了2003—2017年中国283个城市的绿色全要素生产率,并借助创新型城市建设这一准自然实验,采用渐进性的双重差分模型检验了创新型城市建设对绿色全要素生产率的影响。研究发现,创新型城市建设有利于促进中国经济发展的绿色转型,相较于非创新型城市,政策试点使得绿色全要素生产率平均提高4.9%。具体地,创新型城市建设可以通过技术效应、集聚效应和倒逼效应三条途径驱动绿色全要素生产率的提升。异质性分析表明,创新型城市建设对东部地区城市、规模较大城市以及高等级城市绿色全要素生产率的促进效应更强。分位数估计结果显示,创新型城市建设对城市绿色全要素生产率的效应呈边际递增趋势。文章研究结论稳健,经过平行趋势检验、PSM-DID方法估计、反事实检验、安慰剂检验、其他稳健性检验以及工具变量估计之后,依然成立。由此得出,在创新型城市建设过程中,要坚持因地制宜、因城施策、一地一策的原则,充分发挥地方政府的主体地位,同时要探索创新型城市建设政策促进城市绿色全要素生产率提升的多维途径。

In the framework of DEA,based on the directional distance function considering the unexpected output,this paper used the Global-Malmquist-Luenberger productivity index to measure the green total factor productivity of 283 cities in China from 2003 to 2017.Then,we took innovative city construction as a quasi-natural experiment,and used the gradual DID(difference-in-differences)model to estimate the impact of innovative city construction on green total factor productivity(GTFP).The study found that the construction of innovative cities was conducive to the green transformation of China s economic development.Compared with non-pilot cities,the GTFP of innovative pilot cities increased by 4.9%on average.Specifically,the construction of innovative cities could achieve innovation-driven urban green development in three ways:innovation effect,agglomeration effect and reverse force effect.Heterogeneity analysis found that the construction of innovative cities had a greater promoting effect on GTFP of cities in the eastern region,larger cities and cities with higher levels.Quantile estimation results showed that the effect of the construction of innovative cities on urban GTFP was increasing marginally.The conclusion of this study was robust,which still held after parallel trend test,PSM-DID method estimation,counterfactual test,placebo test,other robustness tests and instrumental variable estimation.This study has the following implications:In the process of building innovative cities,we should adhere to the principle of adjusting measures to local conditions,implement the‘one policy for one place’principle,give full play to the dominant position of local governments,and explore multi-dimensional ways to promote the level of GTFP of the city.