人口与经济2026，Vol.47Issue(3)：27-41,15.DOI:10.3969/j.issn.1000-4149.2026.00.018
生育行为的年龄密码
The Age Code of Reproductive Behavior:A Simulation-Based Forecast of Complete Fertility Determinants and Trajectories Based on the Age at First Birth
摘要
Abstract
As China's total fertility rate continues to decline and the population enters a phase of negative growth,it has become increasingly crucial to scientifically forecast the dynamics of fertility levels and improve fertility support policies.Ideally,individuals'intended fertility and their complete fertility should converge.However,discrepancies often exist in reality,making it difficult to accurately predict complete fertility based solely on intended fertility.The age at first birth,as a temporal indicator of an individual's initial fertility behavior,exhibits a strong correlation with both intended fertility and complete fertility.This paper attempts to construct an theoretical framework of"intended fertility-age at first birth-complete fertility".Drawing on three waves of CLDS data(2014,2016,and 2018),we employ the CatBoost machine learning model to capture nonlinear relationships and interaction effects among variables,and further simulate and predict the complete fertility of the childbearing-age population.The study finds that:1)The correlation between age at first birth and complete fertility presents complex nonlinear patterns under the interaction of other socioeconomic variables.2)Incorporating age at first birth into the predictive model can effectively mitigate the bias inherent in estimating complete fertility based solely on intended fertility.3)Particular attention should be paid to the fertility challenges faced by childbearing-age individuals with delayed first births,as well as those residing in urban areas,and in the Northeast and Eastern regions of China.To address the challenge of population decline in China,we propose establishing a"timing-parity"dual-dimensional incentive policy framework.This approach would implement tiered subsidies based on the parity and age at first birth of childbearing-age individuals,and further enhance the targeting and effectiveness of policies by incorporating multiple influencing factors and adapting measures to local conditions.关键词
意愿生育数量/初育年龄/终身生育数量/机器学习/CatBoost模型Key words
intended fertility/age at first birth/complete fertility/machine learning/CatBoost model分类
社会科学引用本文复制引用
王亚楠,徐秋婷,韩菡..生育行为的年龄密码[J].人口与经济,2026,47(3):27-41,15.基金项目
国家自然科学基金面上项目"'大小兼容'的农地连片经营:代际变迁视角下供给条件与协调机制研究"(72473036) （72473036）
江苏省社会科学基金青年项目"乡村振兴背景下江苏农业用地集中流转发展研究"(22GLC014) （22GLC014）
河海大学中央高校基本科研业务费项目"城乡融合视域下人口流动网络格局演变、驱动机制及优化路径研究"(B250207065) （B250207065）
教育部人文社会科学基金规划项目"承包地经营退出视角下农户参与行为与协调机制研究"(24YJA790069). （24YJA790069）
