Research On Population Structure Prediction In China Under The Comprehensive Two-child Policy

As a large population country,population problem has always been the core of China's policy formulation and development planning,and the population environment has important influence on our country's economy,society,resources and environment,so that the total population stability in a sustainable state keeps our population age structure and gender structure balance,For our country's future economic and social development has profound significance.China's population policy has undergone several decades of evolution,since the 1970 's since the implementation of the family planning policy has been after more than 40 years,the implementation of family planning to solve the rapid increase in the total population growth rate and so on,improve our people's living standards and per capita resource share,improve the national quality,So that our country experienced the 30 rapid economic development of the demographic dividend period.However,any policy contrary to the laws of nature has its two sides,since entering the 21 st century,China's population,economic and social situation has undergone great changes,there has been an imbalance in the birth rate of the population,the aging process accelerated,the proportion of the labor force decline,demographic dividend into a demographic debt and other phenomena,Become an urgent problem that affects the further development of China's economy and society.In this context,in December 2015,the comprehensive two-child policy has been formally implemented since January 1,2016.This paper is based on the implementation of the comprehensive two-child policy,through the Leslie Population forecast model forecast analysis of the implementation of comprehensive two-child policy,for the formulation of China's population policy to provide a scientific basis.At first,this paper analyzes the effect of the implementation of China's family planning policy,analyzes the population problems faced by our country at present,and makes a descriptive statistical analysis of the effect of the implementation of the comprehensive two-child policy so far.Then,the domestic and foreign population prediction models are briefly analyzed,the advantages and limitations of the analysis are compared and the Leslie model is chosen.Secondly,we forecast and revise the sex ratio of the birth population through the GM(1,1)grey forecasting model,and through the establishment of the Leslie model,we forecast the future population and population structure development under the family planning policy and the comprehensive two-child policy respectively.Compared with the analysis,the implementation of the comprehensive two-child policy can alleviate the speed and magnitude of the decline of the total population in China,In 2050,the decline to 1.2755 billion,compared with the family planning policy increased by 170.7 million,but the change of fertility policy is not effective in delaying the process of aging of our country,can not reverse the disappearance of China's population dividend,the proportion of the workforce continues to decline,by 2050,the proportion of our elderly population as high as Population dependency ratio is as high as 71.91%.The innovation of this paper is as follows: First,this paper is based on the family planning policy and the comprehensive two-child policy of the prediction of comparative analysis,the different fertility policy as a prerequisite for population prediction,and using Matlab programming,finally reached the implementation of comprehensive two-child policy and the future trend of population development.Secondly,the model parameters are defined in detail,and the prediction of sex ratio at birth is based on the method of combining the quantitative analysis of GM(1,1)model with qualitative analysis,and revising the prediction data of sex ratio according to the International normal value field and the actual development trend of our country.