生育政策与家庭微观决策及宏观经济结构

Family Planning Policy,Micro Decisions and Macro Economic Structure

本文根据中国传统文化和家庭行为的特征事实,构建了新的家庭效用与决策函数模型,融合了"养儿防老"等传统情结,将生育决策、子辈人力资本投资和代际收入转移同时内生化。本文模型兼顾了父辈对子辈的"利他动机"和"交换动机",考虑了子辈对父辈来讲兼具的"消费"和"投资"的双重效应。在这些关键设定之下,模型的理论推导与数值模拟发现:第一,生育政策会通过人力资本投资和代际收入转移渠道影响代际流动性;第二,虽然生育政策可提高人均产量,但子辈数量受限影响其"消费效应"和"投资效应"的功能充分发挥,造成资源错配,导致父辈期望效用反而下降;第三,金融市场的完善与开放可以部分抵消生育政策对代际流动性、父辈效用和宏观经济结构的负面影响。本文模型有助于解释2000年以来中国的低利率和技能溢价增长放缓等现象,为全面分析生育政策对社会公平和效率带来的影响提供了理论框架。

This paper establishes a new theoretical model to explain several stylized facts in China.The model catches both the altruism and exchange motives between parents and children,and children generate both consumption and investment effects for parents.We incorporate endogenous fertility choices,saving,human capital investment and intergenerational income transfer decisions into an overlapping generation framework(OLG).To the best of our knowledge,this is the first model that incorporates all these choices and mechanisms endogenously,integrating frameworks from previous literatures.We then use this model to analyze the one-child policy implemented in China.Model results show fertility restriction affects social mobility and household utility through several different channels.The model is motivated by following stylized facts:1)Fertility decisions are positively related to income levels in China.2)Education expenditure rates on children for Chinese households are negatively related to total consumption levels.3)Intergenerational income transfers(from children to parents),which are common in Chinese society,are positively related to income of children and negatively related to income of parents.4)Interest rates remained low and skill premium growth rates declined after 2000 s.This model generates results that are consistent with empirical facts and we claim the"dual-motive"and"dual-effect"setups are of importance to fully understand the behaviors of Chinese households.As the one-child policy has been implemented in China since 1980 s,it not only affected macroeconomics directly by reshaping demographics,but also generated indirect influences by distorting household decisions.We employ this model to investigate the influences of fertility restrictions on two indicators:social mobility and household utility.Regarding social mobility,there are two channels that correlate incomes across generations:human capital investment(education expenditure)channel and inter-generational income transfer channel.These two channels are affected by fertility restrictions and financial frictions.Firstly,as long as credit constraints are absent for all households,the fertility restriction does not affect the human capital investment channel.Secondly,even without credit constraints,fertility constraint still increases inter-generational income correlations through income transfer channel,harming social mobility.Regarding household utility,the influences of fertility restrictions are contingent on financial market openness.Under closed financial market,there are three channels through which the policy affects expected utility of households.Firstly,fertility restriction increases per-capita output and expected income by increasing per-capita human capital and physical capital,generating positive effects on household utility.The other two channels,however,both have negative effects.Secondly,from the perspective of consumption effect of children,fertility constraint restricts free quantity-quality tradeoff of offspring,distorting consumption expenditure.Thirdly,from the perspective of investment effects of children,fertility restriction limits the saving vehicles of households,distorting cross-age allocations of wealth.Therefore,although fertility restriction improves budget constraints of households,their expenditure options are highly restricted,intra-temporally and inter-temporally.Nevertheless,when financial market is open to international market,the third channel shuts down,partially mitigating misallocations caused by the policy.Therefore,model results discover multiple new channels that fertility restrictions harm social mobility and household welfare,even if the policy generates a positive effect on economic growth.Notice these channels and implications are unique results of integrating dual-motive of parents and dual-role of children into one framework.This model illustrates following policy implications:1)In addition to releasing fertility constraints,deep reforms on healthcare system,education system and labor market are necessary to reduce raising cost and increase fertility rate,which is crucial for the functionality of allocating resources through traditional mechanisms.2)Further development on financial market and social security system are necessary to maintain high social mobility and household welfare given fertility restrictions.3)Opening capital market can help to mitigate distortions created by fertility constraints.