Investigating Coupling Coordination Between Urban Development and Ecological Efficiency: Evidence from the Yangtze River Delta

This paper investigates the evolution and driving mechanisms of the Coupling Coordination Degree (CCD) between urban development (UD) and ecological efficiency (EE) in the Yangtze River Delta (YRD) urban agglomeration. Using panel data for 27 cities from 2013 to 2023, a comprehensive evaluation model and the CCD model are used to measure the level of coordination across cities. A fixed-effects panel regression model is constructed to systematically examine the effects of economic development and education expenditure on CCD, focusing on the moderating role of education expenditure. The empirical results indicate that: (1) CCD in the YRD shows a clear upward trend, gradually shifting from disorder to coordinated development; (2) inter-city disparities remain evident, reflecting differences in development foundations, industrial structures, and governance capacities; (3) economic development significantly promotes CCD by providing material and institutional support for urban–ecological coordination; and (4) education expenditure strengthens this positive relationship by enhancing human capital accumulation and knowledge spillovers. The findings highlight the importance of integrating economic growth with human capital investment to promote green and high-quality urban development.