关键词: 基础设施, 经济增长, 中介效应, 规模效应

Abstract: The infrastructure can directly promote economic growth as special capital stock, and indirectly promote economic growth by promoting investment and labor (increasing the quantity of production factors) and increasing the marginal productivity of capital and labor (improving the efficiency of production factors). This paper constructs an extended Barro economic growth model, and tests the two mechanisms by using China's provincial panel data from 1992 to 2016 and the intermediary effect model. The results show that the infrastructure can promote economic growth. But there exists heterogeneity in transportation, energy and communication infrastructure and in the time before and after the financial crisis in 2008. The direct effect shows a dynamic upward trend, while the intermediary effect decreases gradually. This paper further uses the nonlinear model to test the reasons of the heterogeneity. The results show that the promotion effect of infrastructure on economic growth in China is mainly scale expansion, quantity or extensionstyle, not quality or connotationstyle. The total effect of energy and communication infrastructure on economic growth has scale effect, while the scale effect of transportation infrastructure is not significant. However, transportation infrastructure also has a continuous promoting effect on economic growth, which shows that there is still a large investment potential for these three types of infrastructure in China, and the key is to improve the efficiency of production factors through infrastructure construction.

Key words: infrastructure, economic growth, mediation effects, scale effect