Do national urban agglomeration policies reduce regional disparity? Evidence from nineteen urban agglomerations in China

Currently, China faces the challenge of balancing economic growth with regional coordinated development. The rapid development of China's economy has attracted widespread attention worldwide, yet issues such as the north–south divide and the decline of the northeast region have constrained the achievement of coordinated regional development. To narrow the regional development disparity, national urban agglomeration policies have received significant attention as a new urban agglomeration model. Based on panel data of prefecture-level cities in China from 2003 to 2020, this paper calculates the regional development disparity of 19 national urban agglomerations and considers the State Council's approval of national urban agglomerations as a quasi-natural experiment, using a multi-period difference-in-differences model to assess the impact of this policy on the regional development disparity. The results shows that national urban agglomeration policies have widened the development disparity within national urban agglomerations, which remains valid after a series of robustness tests. Heterogeneity analysis reveals that the impact of national urban agglomeration policies on regional development disparity exhibits spatial heterogeneity. Specifically, compared to national urban agglomerations in the north, the policy significantly increases the regional development disparity in southern national urban agglomerations. Compared to national urban agglomerations in the development and expansion stage, the policy significantly widens the regional development disparity in national urban agglomerations that are in the optimization and enhancement stage. Additionally, the policy significantly enlarges the regional development disparity in national urban agglomerations with smaller populations and smaller areas. Further analysis finds that national urban agglomeration policies not only expand the development disparity within national urban agglomerations but also between different national urban agglomerations. Based on these findings, we recommend implementing differentiated policies to coordinate the relationships between national urban agglomerations and to prioritize overall regional coordinated development at a broader level.