生命周期视角下全球实际利率决定的审视——供给与需求效应的对比分析

Research on the Global Real Interest Rate Decision from the Perspective of Life Cycle——Comparative Analysis of Supply and Demand Effects

人口变迁深刻影响着全球经济的发展,而造成这一现象背后的根本原因是生育决策的内生变化。本文在构建两期世代重叠模型(Two-Period OLG Model)中内生引入生育决策的各维度变量,重点探讨不同人口数量选择、人口结构转变及人口质量提升对实际利率产生的不同作用,并利用全球137个国家或地区1960—2017年数据研究发现,生育决策的不同维度对实际利率的作用存在显著差异。其中,人口数量正向影响实际利率,表现出供给效应,即生育决策下降导致人口增长放缓会通过降低劳动供给引致资本边际产出下降,最终压低实际利率;人口质量负向影响实际利率,即增加健康与教育投入引起的预期寿命延长最终会降低实际利率,表现出需求效应;人口结构对实际利率的作用由需求效应主导,凸显抚养人群比例上升带来的经济效应。本文提供了一种理解实际利率行为的人口学解释,揭示了生育决策的内生变动会带来未来实际利率趋势的有效信息,从另外一个视角给出利用人口政策的"时间窗口"改变负利率局面的政策切入点。

The demographic transition has profoundly affected the development of the global economy, and the fundamental reason behind the dramatic changes in population is the endogenous changes in fertility decisions. The change of fertility decision will affect the real interest rate through the change of population quantity, structure and quality, and have different influences on the real interest rate.This paper endogenously introduced various dimensional variables of fertility decision-making in the Two-Period OLG Model, focusing on the differences in the effects of different dimensional indicators on real interest rates from the perspective of supply and demand effects. Based on the data of 137 economies from 1960 to 2017, the research found that the different dimensions of fertility decision-making have significant differences in the effect of real interest rates. The population has a positive impact on the real interest rate, showing a supply effect. The slowdown in population growth brought about by declining fertility decisions will reduce the supply of labor, resulting in a decline in the marginal output of capital, and ultimately depressing the real interest rate. Population quality negatively affects real interest rates, which means the extension of life expectancy caused by increased health and education investment will eventually reduce real interest rates, showing a demand effect. The effect of population structure on real interest rate is dominated by demand effect, which highlights the economic effect brought by the increasing proportion of dependants.This paper puts forward three suggestions. Firstly, the monetary authorities must grasp information on population dynamics and improve their ability to adjust and control monetary policy in an aging society. Secondly, while comprehensively assessing the expected effects of the latest birth policy, we should learn from international experience and actively promote the reform of the social security system. Thirdly, we should pay attention to and grasp the“pure elderly needs”brought by aging and the changes in social consumption trends, thus embracing the various opportunities nurtured by the“transitional era”.