本项目研究目前中国经济面临的低生育率问题及潜在的促进人口增长的政策。我们以家庭的微观经济决策为立脚点，通过具有代际利他主义偏好的父母的最优生育孩子的数量、消费、对子女的教育及代际转移财富的最优选择，理解加总宏观经济变量的表现，从中找到目前中国家庭较低的生育意愿的根本经济原因。我们的模型是新古典增长理论的一个自然拓展，内生考虑父母生育子女的数量，及孩子最优受教育年限与教育的投入。我们提出的这个框架是国际主流宏观经济学研究家庭生育率决策的Barro-Becker 模型与人力资本生产的Pen-Porath模型的有机结合体。我们用数据校准模型，定量评价几类潜在促进人口增长的政策，如完全放开生育率选择的限制、根据孩子的数量给予的线性和非线性补贴、根据孩子数量和收入水平给予的收入补贴、和增加公共教育的投入这几类政策。研究的初步结果显示增加公共教育的投入更有利于促进人口增长及人均和社会福利的提高。

This project studies current low fertility rate of Chinese economy and some potential policies aiming at promoting population growth. Based on optimal household level choices made by dynastic altruistic parents, including number of children, consumption, educational length, private expenditure on education, and transfer from parents to children, we aggregate these micro-level variables and understand macroeconomic performance. We explore key economic reasons why Chinese people do not want to have more children in recent years. Our framework extends the Neoclassical growth theory by endogenously considering the fertility and educational choices faced by altruistic parents. It combines two mainstream macroeconomic models in analyzing family decisions of fertility and education, Barro-Becker model and Ben-Porath model. In the calibrated model using Chinese data, we quantify the level of fertility, years of education, educational expenditure, transfer from parents to every child, and other variables. More importantly, we evaluate several types of policies that could potentially promote population growth. They include, policy without any restriction on fertility choice, linear and nonlinear subsidy on fertility, subsidy based on both income and fertility, and higher expenditure on public education. Our preliminary result indicates that higher investment on public education exerts more effect in promoting population growth and average and social welfare than other policies under concern.