中国城镇家庭储蓄率之谜——基于年龄—时期—组群分解的再考察

The Puzzle of Chinese Urban Household Savings Rate——A Revaluation with the Age-Period-Cohort Decomposition

经典的生命周期假说认为,储蓄率—年龄曲线呈倒U型,但基于年龄—时期—组群(APC)分解法对中国城镇住户调查(UHS)数据的研究并不支持生命周期假说的预测,一些研究发现中年户主家庭储蓄率相对较低,另一些研究则发现家庭储蓄率随着户主年龄不断上升。本文对此进行了深入研究,发现APC分解中的共线性识别方法不一致是产生上述分歧的原因。基于对四种不同的共线性识别方法的比较,本文认为城镇中年户主家庭储蓄率较低的正U型曲线比较符合中国实际。本文还发现城镇家庭储蓄率—户主年龄曲线在1996年前后发生了转变,由倒U型转为正U型。关于中年户主家庭储蓄率较低的原因,本文通过对UHS1988—2009年、CFPS中国家庭追踪调查2010—2016年数据的分析发现,城镇家庭中正在上大学、上高中的学生人数能够解释中年户主家庭的储蓄率为什么偏低。本文推测20世纪90年代中期开始的家庭教育负担的上升,可能是城镇家庭储蓄率—户主年龄曲线发生转变的原因。本文的研究澄清了关于中国城镇家庭储蓄率—户主年龄曲线形态的分歧,并揭示了解释城镇家庭储蓄率—户主年龄正U型之谜的新方向。

The classical life cycle hypothesis predicts that the savings rate age curve is inverted U shaped,but the researches using APC decomposition and UHS data do not support the prediction of life cycle hypothesis.Some studies find that the savings rate of middle age households is relatively low,while others find that the savings rate of households increases with the age of household heads.This paper makes a thorough study of this problem and finds that the reason for the divergence is the inconsistency of the collinearity identification methods in APC decomposition.Based on the comparison of four different collinearity identification methods,this paper finds that the positive U shaped curve with lower savings rate of middle age households is more in line with China’s reality.This paper also finds that the urban household savings rate age curve has changed from inverted U to positive U around 1996.With regard to the reasons for the low savings rate of middle age households,this paper analyses the data of UHS from 1988 to 2009 and CFPS from 2010 to 2016,and finds that the number of children in college and high school of households can explain why the savings rate of middle age households is the lowest.This paper speculates that the increase of education burden since the mid-1990s may be the reason for the change of the urban household savings rate age curve.This paper clarifies the divergence of the urban household savings rate age curve in China,and reveals a new direction of explaining the puzzle of the positive U shape of urban household savings rate age curve.