Public–Private Partnership Infrastructure Investment and Sustainable Economic Development: An Empirical Study Based on Efficiency Evaluation and Spatial Spillover in China

Public–private partnership (PPP), an innovative mode of infrastructure investment, has been widely applied in China and has become an essential policy tool with which to promote sustainable economic development. In order to comprehensively evaluate the economic consequences, using 31 provinces in China from 2003 to 2018 as samples, first, stochastic frontier analysis was performed to measure the input–output efficiency of infrastructure investment to evaluate the economic sustainability and efficiency of PPP compared to single government-led investment mode. Next, the overall economic growth effect of PPP was verified. Further, from the perspective of sustainable development of regional economies, the double-fixed effect spatial Durbin model was adopted to empirically test the spatial spillover effect of PPP and clarify its industrial heterogeneity. The results show the following. (1) The average input–output efficiency of infrastructure is 0.449, revealing a distribution law of decreasing from east to west and remarkable regional variation. However, a good trend of improvement emerged, reflecting the economic sustainability of infrastructure investment, and PPP has played a positive role in promoting it. (2) PPP has significant and positive economic growth and spatial spillover effects, which can promote regional economic integration, embodying its economic sustainability function. (3) The economic impact of PPP has significant industrial heterogeneity. Transportation PPP can bring greater economic benefits, confirming the vital position of transportation infrastructure in the sustainable development of regional economies. Energy and water PPP have positive externalities. All of this provides powerful and reliable proof of the realization of sustainable economic development under the regional virtuous circle driven by infrastructure investment through PPP.