The Impacts of Neighborhoods on Intergenerational Mobility II: County-Level Estimates*
中文摘要
我们估计美国每个县对儿童成年后收入的因果效应。首先，我们估计一个固定效应模型，该模型通过分析携带不同年龄子女跨县迁移的家庭得到识别。随后，我们利用这些固定效应估计值：（i）量化地区对代际流动性的影响有多大；（ii）预测在每个县成长的因果效应，为寻求迁往更有机会的地区的家庭提供指引；（iii）刻画哪些类型的地区能带来更好的结果。对于在低收入家庭中成长的儿童，童年期间每在成长效应好一个标准差的县多生活一年，成年后收入就增加0.5%。即便在同一大都市区内，各县的因果效应也存在很大差异。贫困集中度较低、收入不平等程度较低、学校较好、双亲家庭占比较高且犯罪率较低的县，往往能为贫困家庭的儿童带来更好的结果。男孩的结果在地区间的差异比女孩更大，而且在高度隔离的地区，男孩的结果尤其差。能带来更好结果的地区，平均房价更高，但我们的方法发现了许多“机会性价比高的地区”——这些地区能带来良好结果，房价却并不十分昂贵。
Abstract
We estimate the causal effect of each county in the United States on children's incomes in adulthood.We first estimate a fixed effects model that is identified by analyzing families who move across counties with children of different ages.We then use these fixed effect estimates to (i) quantify how much places matter for intergenerational mobility, (ii) construct forecasts of the causal effect of growing up in each county that can be used to guide families seeking to move to opportunity, and (iii) characterize which types of areas produce better outcomes.For children growing up in low-income families, each year of childhood exposure to a one standard deviation (std.dev.) better county increases income in adulthood by 0.5%.There is substantial variation in counties' causal effects even within metro areas.Counties with less concentrated poverty, less income inequality, better schools, a larger share of two-parent families, and lower crime rates tend to produce better outcomes for children in poor families.Boys' outcomes vary more across areas than girls' outcomes, and boys have especially negative outcomes in highly segregated areas.Areas that generate better outcomes have higher house prices on average, but our approach uncovers many "opportunity bargains"-places that generate good outcomes but are not very expensive.