The Impact of Industrial Complementarity on Urban Productivity and Spillover Mechanisms: Evidence from the Pearl River Delta of China

Against the backdrop of the accelerated advancement of regional economic integration, industrial synergy in urban agglomerations has become a core pathway to break homogeneous competition, enhance urban productivity and achieve sustainable economic growth, yet existing studies have mostly focused on the local effects of industrial agglomeration, and complementary linkages from the perspective of industrial chain supply and demand, as well as their cross-city spatial spillover mechanisms, remain insufficiently explored. Taking the nine cities in the Pearl River Delta (PRD) as the research object, this paper constructs an Industrial Complementarity index (ICI) based on urban panel data from 2012 to 2017 and multi-regional input–output tables. The findings reveal the following: (1) Industrial complementarity in the PRD exhibits significant uneven distribution characteristics, with the network structure gradually evolving from a single-core concentrated pattern centered on Shenzhen in 2012 to a multi-polar dispersed pattern centered on Zhaoqing, Zhongshan, and Dongguan in 2017. Resource-based cities play a key fundamental connecting role in the intermediate input supply network. (2) Industrial complementarity significantly promotes urban productivity growth, and its impact is mainly realized through spatial spillover channels. Moreover, productivity spillovers show an obvious distance decay characteristic, and marginal cities obtain significantly higher marginal benefits from spillovers than core cities. (3) Mechanism tests indicate that financial deepening and human capital accumulation are important channels through which industrial complementarity affects urban productivity.