Decoding China's urban agglomerations policies: A scientific evaluation and exploration of economic benefits

Urban agglomerations planning policies are a critical driver for sustainable urban development. The Chinese central and local governments have implemented a series of policies to guide the development of urban agglomerations. However, the scientific soundness of these policies and their impact on promoting high-quality urban economic development have received limited attention. This study addresses this research gap by examining the scientific rationale of China's urban agglomerations policy formulation through the policy modeling consistency (PMC) index model. Then, it empirically assesses the economic effects of policy implementation using a difference-in-differences (DID) model based on statistical data from 182 cities spanning 2000 to 2021. The results show that: (1)while the overall level of urban agglomerations policies is excellent, there are areas for improvement, such as policy objectives, implementation, and financial support; (2) Urban agglomerations policies contribute to a 1.8% increase in high-quality economic development; (3) Mechanisms underlying policy effect include the scale effect of industrial agglomerations, the radiation effect of infrastructure construction, and the spillover benefits of advanced industrial structure. Moreover, the effects of policy vary across urban agglomerations of different scales, with larger urban agglomerations demonstrating more substantial benefits. The research outcomes provide valuable insights for policymakers in formulating scientifically and economically beneficial urban agglomerations policies.