How to understand push-pull theory

The theory put forward by American Li Zhengdao

Push-pull theory holds that labor migration is caused by the wage difference between the place where people move in and the place where they move out. Modern push-pull theory holds that in addition to higher income, the push-pull factors of migration include better jobs, better living conditions, better educational opportunities for themselves and their children, and better social environment.

In 1960s, American scholar Li Zhengdao put forward a systematic theory of population migration-"push-pull theory". For the first time, he divided the factors affecting migration into "thrust" and "pull". He thinks the former is a negative factor, because these factors prompt immigrants to leave their original place of residence; The latter is a positive factor, because these factors attract immigrants who want to improve their lives to move into new places of residence.