This effect means that the central regional cities mainly rely on the agglomeration of peripheral production factors in the growth period, and the surrounding towns or small and medium-sized towns gradually gather in the central cities, bringing all kinds of high-quality resources to the regional centers, which has a certain impact on the development of small and medium-sized cities in the region.

Cities in the central region are constantly developing. When they grow into big cities or even first-tier super-large cities, they have abundant capital because of high-quality medical care, education and infrastructure resources. It will attract talents, investment, population, information and other high-quality resources from vulnerable areas. For big cities, this will lead to further improvement of competitiveness and further expansion of scale.

The simple understanding is that the cities are getting better and better or the big cities are getting better and better, and the surrounding cities will develop slowly.