Prediction Of Population Size and Age Structure in China Based on Grey Prodiction and Leslie Model

Abstract

Population is a major problem that restricts China's comprehensive, coordinated and sustainable development. Therefore, it is of great significance to establish a model that can accurately predict the population and age structure. This paper uses GM (1,1) to obtain the gender ratio of future newborn population and total population, quantifies the three-child policy as the increase in the fertility rate of women of childbearing age, uses the Leslie model to obtain the female population at all ages, and finally gets the national population and age structure in the next five years under the background of the three-child policy. The results show that the opening of the three-child policy positively impacts the increase of the newborn population and the growth rate of the total population in the early future. But as time goes by, it still cannot restrain the decrease in the newborn population and the net increase of the total population. In addition, the aging problem has not been effectively improved in the short term. In the next five years, the proportion of the aged population continues to rise, while the young population gradually decreases. In terms of the labor force coefficient, there will be a downward trend from 2021 to 2025 and a slight increase from 2025 to 2026.