数字经济推动了城市绿色全要素生产率提升吗?——基于“宽带中国”试点的证据

Does Digital Economy Drive City Green Total Factor Productivity? Evidence from the “Broadband China” Policy

数字经济正成为新发展阶段推动中国绿色变革的重要力量,“宽带中国”是促进数字经济发展的关键举措。本文利用2006—2019年中国281个地级市的面板数据,构建双重差分模型,基于“宽带中国”政策检验了数字经济对绿色全要素生产率的影响,并进一步剖析政策效果差异,结合空间双重差分模型评估了政策的空间溢出效应。研究发现,“宽带中国”政策对绿色全要素生产率存在正向影响。随着政策强度提升,政策效果表现为先上升、后下降、再上升的趋势,呈现出阶段性的“虹吸效应”。在绿色全要素生产率较低的地区,政策效果更好,但在绿色全要素生产率超过一定水平后,“虹吸效应”再次出现。从政策的空间溢出效应来看,总体上“溢出效应”大于“虹吸效应”。

In new development stage,the digital economy is becoming a significant force for green transformation,and “Broadband China” is a vital policy to encourage the development of the digital economy.This paper uses the panel data of 281 cities in China from 2006 to 2019,builds a difference-in-difference model and tests the impact of digital economy on green total factor productivity based on the policy of “Broadband China”.This paper further analyzes the heterogeneity of policy effectiveness and examines the spatial spillover effects of the policy by a spatial DID model.It is found that,the policy of “Broadband China” has a positive effect on green total factor productivity.As policy intensity increases,the policy effectiveness rises,then falls,then rises again,resulting in a phased "siphon effect".The policy impact is stronger in locations with lower green total factor productivity,but the “siphon effect” phenomenon returns if the green total factor productivity reaches a certian level.From the perspective of spatial spillover effects of the policy,in general,the “spillover effect” is greater than the “siphon effect”.