Digital Trade Policy and Port Productivity: Evidence From China’s Cross‐Border e‐Commerce Comprehensive Pilot Zones

To investigate the impact of the cross‐border e‐commerce comprehensive pilot zone (CBECPZ) policy on the total factor productivity (TFP) of Chinese coastal ports, this study uses a balanced panel dataset of 34 coastal port cities in China over the period 2012–2022. Port TFP is measured using the DEA‐based global Malmquist productivity index and is further decomposed into technical efficiency (TE), best‐practice gap (BPG), and scale efficiency (SE). The effect of the CBECPZ policy on port productivity is then identified within a double/debiased machine learning (DML) framework. The results show that the CBECPZ policy significantly enhances port TFP. Further decomposition analysis indicates that the policy significantly improves BPG and SE, whereas its effect on TE is not statistically significant, suggesting that the productivity gains are mainly reflected in movements toward a higher level technological frontier and improvements in SE. The mechanism analysis further shows that the CBECPZ policy significantly promotes urban technological innovation, which in turn enhances port TFP, indicating that technological innovation is an important transmission channel through which the policy affects port productivity. By integrating DML‐based causal identification, port productivity decomposition, and technological innovation mechanism analysis, this study provides new empirical evidence for understanding how digital trade policies affect port productivity and the mechanisms underlying these effects.