邦戈茨生育模型演变及其对中国低生育水平的新解释OACHSSCDCSTPCD

The Bongaarts model is a classic model for exploring the relationship between fertility level,reproductive behavior and reproductive intentions.In the fecundity-based model,Bongaarts identified four intermediate variables:marriage index,contraception index,induced abortion index,postpartum infertility index.At the beginning of the 21st century,Bongaarts pointed out the deviation between fertility levels and fertility intentions,and proposed a modern model based on fertility intentions.Instead of using natural fecundity as a reference,the new model replaced it with fertility intentions,and was advanced by Morgan to form the six-factor multiplicative model which included unwanted fertility,replacement effect,gender preferences,tempo effect,involuntary infertility and competition.The evolution of the model reflects a completely new measurement of fertility levels in different social scenarios,achieving a breakthrough from theory to operationalized application,quantification and mechanism analysis.After analyzing the phenomenon of low fertility in China by using Bongaarts modern fertility model,it is found that gender preferences,delay in the age of first childbearing,dissolution of marriage,and competition are still important factors affecting the realization of fertility intention.We also extend the Bongaarts modern fertility model to include policy factors in the model and find that the policy itself played an inhibitory role in realizing fertility intention,and other factors promoting or inhibiting fertility still had an impact after controlling the policy factors.In addition,as the cohort gets closer,the role of different factors changes,particularly gender preference,marital status and educational attainment.The results of the study are instructive for policy refinement as well as differentiated policy implementation.