Population agglomeration, borrowed size and urban economic growth in China

This study constructed a theoretical framework and measurement model for investigating the effect of population agglomeration on urban economic growth. This framework accounts for both intracity and intercity agglomeration economy and is based on a comprehensive set of indicators of population agglomeration and urban economy. Two hypotheses were tested using data from 285 prefecture-level cities in China from 2005 to 2020, with the data corroborated against data from over 500 Chinese provincial and municipal statistical yearbooks, 4560 statistical bulletins, natural elements such as relief degree of land surface, and DMSP/OLS and NPP/VIIRS matched nighttime lights imagery. We focused on the effects of intercity agglomeration economy, namely borrowed size and agglomeration shadow effects. Our results indicated that intracity population agglomeration had a positive effect on urban economic growth. This effect was moderated by spatial and policy-related factors. In addition, the borrowed size effect was stronger than the agglomeration shadow effect among Chinese cities. Intracity population agglomeration had a significant positive spatial spillover effect. The high degree of agglomeration of neighboring cities positively affected a city's economic growth. It was interesting to note that the impact coefficient of intracity agglomeration dropped by about 0.1 with the inclusion of intercity agglomeration elements.