Can smart cities boost new quality productive forces? Evidence from a DID approach across 270 Chinese cities

This study employs a time-varying difference-in-differences (DID) approach to investigate the causal effect of smart city construction on the new quality productive forces (NQPF), along with regional heterogeneity and moderating mechanisms. The results indicate that smart city construction significantly enhances the NQPF, a conclusion supported by various robustness tests. Compared to non-pilot cities, pilot smart cities exhibit an average increase of approximately 0.38% in the NQPF, with this effect growing over time. The positive impact of smart city construction on the NQPF is statistically significant only in western cities, resource-based cities, and cities with higher administrative ranks. Besides, economic development and innovation levels amplify the marginal enhancement effect of smart city construction on the NQPF, whereas industrialization levels suppress this marginal effect. The findings not only provide empirical support for synergizing urban digital and intelligent transformation with the advancement of the NQPF but also deepen theoretical understanding of their evaluation while fostering integrated research on urban development and the NQPF.