Urban Primacy, Innovation Capacity, and Spatial Spillover Effects: An Empirical Analysis Based on the Spatial Durbin Model

Abstract

Against the backdrop of innovation-driven development, this research explores how urban innovation capacity exhibits spatial spillover effects, particularly in relation to urban primacy. Drawing on panel data from 33 cities in Jiangsu, Hubei, and Sichuan provinces between 2002 and 2022, this study constructs a Spatial Durbin Model (SDM) incorporating bi-directional fixed effects and spatial distance weights. The analysis controls economic scale, industrial structure, R&D expenditure, education level, urban size, foreign direct investment, and infrastructure. Results reveal pronounced spatial heterogeneity: Jiangsu exhibits significant positive spatial linkages, where urban primacy suppresses local and overall innovation but slightly promotes that of neighboring areas, indicating a “coordinated-driven” pattern. In contrast, Hubei exhibits negative spatial correlation, with primacy effects being statistically insignificant. In Sichuan, primacy positively affects both local and neighboring innovation, yet the overall spatial spillover remains negative, suggesting a “siphon effect.” Policy implications highlight the need for strengthening monocentric structures in less developed regions to foster aggregate innovation, while more advanced areas should transition toward polycentric urban systems to mitigate siphoning and promote balanced, highquality development.