Do polycentric megaregions contribute to the economic development of cities in China

Unlike prior studies that usually focus on the overall economic performance of megaregions, this study investigates whether and how the polycentricity of megaregions affects the economic performance of individual cities in China. Empirical results indicate that polycentricity promotes economic development of both large and smaller cities. This arises because spillover effects are more distance-sensitive than siphoning effects, so shorter intercity interaction distances in polycentric systems tilt the balance between borrowed size and agglomeration shadows toward net positive spillovers. Further analysis reveals that polycentric megaregions improve city economic performance through industrial optimization, factor mobility, and infrastructure connectivity. Moreover, the benefits of polycentricity are especially pronounced for lower administrative level cities, and particularly for those in eastern/coastal megaregions and nurturing and emerging megaregions. These findings provide policy implications for improving the performance of cities of different sizes.