Fertility, Regional Demographics, and Economic Integration

To explain the links between population distribution and economic integration, we construct a spatial economics model with endogenous fertility. A higher population concentration increases real wages and child-raising costs, thus lowering the fertility rate. However, people migrate to more populated regions to obtain higher real wages. We show that mobility across regions results in more people flowing into highly populated regions, but lowers fertility rates there. The population growth path resembles a logistic curve in the early phase, but population decreases in the last phase. Additionally, economic integration leads to population concentration and decreases population size in the whole economy.