队列视角的中国人口内在增长水平研究--基于终身生育率两种估计方法的比较

A Study of Intrinsic Population Growth in China in the Perspective of Cohort:Based on the Comparison of Two Approaches Estimating CFR

通过比较终身生育率的两种估计方法,本研究发现,利用同是队列指标的初育年龄测度终身生育率在反向"预测"过去时明显优于总和生育率估计法,而在正向预测未来时则具有更强的稳定性。运用不同的终身生育率估计值测算中国人口内在自然增长率的结果表明,从20世纪70年代初进入生育期的育龄妇女开始,人口的内在增长水平就已为负并持续下降,与此同时,偏高的男女性别比需要高于2.1的更替水平才能保持人口稳定。中国人口1970年以后持续增长的主要原因在于预期寿命的持续提高,以及育龄妇女占总人口比例相对较高。今后生育政策的调整不仅需要关注当年人口出生率即人口金字塔底层的数量变化,而且要考虑对未来人口结构即人口金字塔形状的影响。此外,在监测人口增长时应继续重视初育年龄变化对人口增长的作用。

This paper concludes that the method estimating CFR based on the mean childbearing age at the first birth provides a better estimate compared with that based on TFR statistics in backward 'forecasting',and more stable estimates in forward forecasting. The estimates from the2 approaches both indicate that the intrinsic rate of natural growth has become negative since women entering their childbearing age in the early 1970 s,and continued to decline subsequently. The minimum replacement level required to keep population constant is calculated at the level higher than 2. 1 acknowledged widely because of the higher male-female birth ratio. Chinese population continues to grow after 1970,due to growth in life expectancy,and relatively high ration of women child-bearing to the total. We should pay attention to both the number of birth also the population structure in the future. In addition,the timing of first birth cannot be ignored because of its impact on total number of children a woman may have in whole life.