China’s Independent Opening-Up: Measurement and Policy Evaluation of Pilot Free Trade Zones

Against the backdrop of rising external economic uncertainty, this study develops a multidimensional measure of China’s independent opening-up and evaluates the staggered establishment of Pilot Free Trade Zones (PFTZs). Using a balanced panel of 31 provincial-level regions from 2010 to 2023, we construct an index comprising Open Linkages and Outward Orientation, Openness Structure and Quality, and Independent Capacity and Supporting Conditions for Opening-up. The baseline difference-in-differences estimate is positive, with the dimensional gains concentrated in structural quality and endogenous supporting capacity rather than in external linkage intensity. Heterogeneous-treatment-robust estimators yield the same qualitative dimensional pattern. However, the composite index estimate declines and becomes statistically insignificant when predetermined transportation and financial conditions are additionally incorporated, and Rambachan–Roth analysis shows that inference is sensitive to modest departures from exact parallel trends. The causal interpretation of the baseline estimate is therefore qualified. The estimated natural indirect effect through technological achievement transformation is positive but has a bootstrap p-value of 0.091 and a 95% confidence interval that includes zero; mediation is therefore not statistically established. A supplementary environmental analysis finds a significant decline in carbon emission intensity and weaker evidence of a decline in total CO2 emissions. Overall, the results are most consistent with PFTZ establishment being associated with improvements in the structural quality and endogenous capacity of opening-up, while the magnitude and causal interpretation remain sensitive to identifying assumptions.