The impact of population migration on regional economic gap in the Yangtze River economic belt and its spatial spillover effect

There has always been a debate on whether population migration has an expanding effect or a narrowing effect on the regional economic gap. This paper makes a further analysis of this issue by using the spatial panel data of 104 cities in the Yangtze River economic belt from 2001 to 2017. The main conclusions are as follows: (1) for the overall regional economic gap, there is an inverted “U”-shaped nonlinear relationship between population flow, population migration and economic gap: expansion effect in the early stage, and the convergence effect in the later stage, which is consistent with China’s gradient development strategy and the phased development concept of “the rich first pushing those being rich later, and finally realizing common prosperity”. (2) For the regional economic gap in the province, population flow also shows the role of expanding first and then converging, while population migration only shows the effect of expansion rather than convergence. The difference between population mobility and population migration originates from the spatial transformation of economic behavior and resource allocation brought about by the change of the latter’s household registration. (3) Considering the spatial effect, the endogenous relationship between population migration and regional economic gap becomes relatively complex, but more comprehensive and objective. The effect decomposition shows that population mobility and population migration are ultimately conducive to balanced regional development, with spillover effect playing an important role.