Discovering the spatial heterogeneous constraints of distance on migration from counties to Shenzhen in China

Distance holds significant importance in the decision-making processes of migration flows. Previous studies have predominantly adopted a global perspective to understand distance constraints. However, same spatial heterogeneity exists in distance constraints, and this heterogeneity contributes to understanding of the effect of regional characteristics in human migration. This study answers three questions: Does distance work for all counties in the same way? Why distance works for some counties but does not for others? And what makes distance decay differently among counties? We adopt geographically weighted regression, binary logistics regression, and random forest regression to analyze the migration from counties all over the China to Shenzhen to explore the spatial heterogeneity of distance decay. The results show that distance does not always work, and that demographics and transportation facilities are important determinants of whether distance works. For counties where distance works, distance decay is nonlinearly related to regional development. This non-linear relationship is due to the game between the appeal of intervention opportunities in the nearest new first-tier city, the constraints represented by the socio-economic development of the source county, and the attractiveness of Shenzhen. This further reflects the dynamic interplay between costs and opportunities, give and gain in the decision process of migration.