The effects of sub-central development on the economic growth of provincial capitals: A study based on the DID and PSO-RF models

Abstract

As a core component in deepening reforms and expanding the strategy of dual circulation development, the importance of developing sub-centers for the economic growth of provincial capitals is self-evident. This paper, based on panel data from 300 prefecture-level cities in China from 1998 to 2020, constructs a progressive double-difference (DID) model to assess the impact of sub-central development on the economic growth of provincial capitals. The research reveals that the development of sub-centers at the provincial level significantly promotes the economic growth of provincial capitals. Moreover, the policies of sub-center cities have a more pronounced stimulating effect on the economic growth of provincial capitals in the central and western regions. Additionally, the more sub-center cities there are, the more apparent the effect on promoting the economic growth of provincial capitals. Subsequently, this paper employs the Particle Swarm Optimization - Random Forest (PSO-RF) model through machine learning to validate the above conclusions, confirming the validity of the findings.