The impact of provincial port integration on port efficiency: Empirical evidence from China's Coastal Provinces

Port integration with the provincial territory as the primary spatial carrier has become an important initiative to implement port reform in China. Objectively evaluating and verifying its effectiveness is essential for refining and promoting this policy. This study empirically examines the effect of provincial port integration (PPI) on port efficiency from a provincial perspective by constructing the multi-period difference-in-differences (DID) model with the panel dataset of China's 9 coastal provinces from 2004 to 2019. The results show that: (1) Implementing PPI can significantly improve provincial port efficiency (PPE), but its impact on green provincial port efficiency (GPPE) is not significant, implying a lack of coordination between port integration and regional ecological protection. This conclusion remains robust to multiple scenarios, including truncated double bootstrapping approach test, placebo test, and endogeneity check. (2) The heterogeneity analysis demonstrates that PPI has a more significant incentive effect on PPE in smaller-scale provinces, provinces with lower levels of port specialization, provinces with larger port size, and provinces that implemented PPI after 2015. (3) Moderate administrative participation is more conducive to exerting the effect of PPI on PPE, and this effect presents an "inverted U-shaped" change characteristic as PPE increases.