Research on the Change of Birth Cohort Size and Its Social Effect in Metropolis：the Case of Beijing

Using birth data of Beijing from 1981 to 2016, this paper discusses the characteristics and trends of birth cohort size in metropolis like Beijing. Result shows the change of birth cohort size in Beijing is totally different from the whole country. Family planning policies, age structure and traditional fertility culture collectively lead to these results. Planning and allocation of public resource doesn’t match the change of birth cohort size in Beijing, birth cohort size imposes squeezing effect on public resource, and this effect transfers to members of birth cohort. So the public policies should respond to the change of birth cohort size to make sure people born in different birth cohort can enjoy the equal outcomes of social development.