Population Structure Analysis Of Sichuan Province Under "Comprehensive Two-child" Policy Based On Leslie Model

The population problem has always been the core issue of human development.With the continued reduction in the fertility rate in our country,the population structure in our country has changed,and at the same time it will also bring about corresponding demographic effects.As a province with a large population,Sichuan Province,combined with the implementation of a comprehensive second-child birth policy,has a strong practical significance in predicting the future population structure of Sichuan Province.This paper selects the Leslie model as the basic model,and then constructs a Leslie population structure prediction model under the “comprehensive two-child”policy.The model mainly involves three parameters of fertility,survival rate,and population sex ratio of women of childbearing age.First of all,establish a fertility parameter model.Since the fertility data in Sichuan are missing a lot,relevant indicators affecting fertility are found through correlation analysis of existing data,and the potential laws of these data are trained using the BP artificial neural network model.The province's total fertility loss value is used for deep learning prediction,and the proportion of women of childbearing age in each age group is used to calculate the fertility rate of women of childbearing age in each age group.Next,the determination of the fertility rate of women of childbearing age in Sichuan after the“comprehensive two-child” policy is based on the policy of “two single and two children” and the policy of “separate two children” on the fertility rate of women of childbearing age.On the other hand,it also combines The survey data of the national fertility level and the survey probability of the relevant investigators' willingness to fertility of provinces and cities after liberalizing the “two-child” policy,taking into account the randomness of the survey data,the fertility rate will fluctuate up and down,so this paper establishes The relaxation combination model predicts fertility rates for women of childbearing age by age.Secondly,weighted average method isused to give more weight to similar years,and a survival parameter model is established.Finally,a gray forecasting method was used to establish a population sex ratio parameter model.Based on the parametric model,a Leslie population prediction model was established.Forecasting the population structure of Sichuan Province,and then put forward countermeasures and suggestions for future researchers to provide a reference for the literature,but also provide a rational reference basis for the policy makers and decision makers in the province.