The Impacts of Neighborhoods on Intergenerational Mobility I: Childhood Exposure Effects*
中文摘要
我们通过研究美国超过700万个在通勤区和县之间迁移的家庭，表明儿童成长的邻里环境塑造了其劳动收入、大学入学率以及生育和婚姻模式。利用家庭迁移时儿童年龄的差异，我们发现邻里环境具有显著的童年暴露效应：对于迁入更好邻里环境的家庭中的儿童，其结果变量的改善程度与其在该地区成长的时间成线性比例，每增加一年暴露时间，约改善4%；邻里环境的好坏以原已居住在当地的儿童的结果变量衡量。我们通过比较同一家庭内兄弟姐妹的结果变量、研究被迫迁离冲击引发的迁移，以及利用预测地点效应在不同出生队列、性别和分位数之间的急剧变化开展过度识别检验，将邻里环境的因果效应与混杂因素区分开来。研究结果表明，邻里环境主要通过童年暴露影响代际流动性，这有助于调和既有文献中相互冲突的结果。
Abstract
We show that the neighborhoods in which children grow up shape their earnings, college attendance rates, and fertility and marriage patterns by studying more than 7 million families who move across commuting zones and counties in the United States. Exploiting variation in the age of children when families move, we find that neighborhoods have significant childhood exposure effects: the outcomes of children whose families move to a better neighborhood—as measured by the outcomes of children already living there—improve linearly in proportion to the amount of time they spend growing up in that area, at a rate of approximately 4% per year of exposure. We distinguish the causal effects of neighborhoods from confounding factors by comparing the outcomes of siblings within families, studying moves triggered by displacement shocks, and exploiting sharp variation in predicted place effects across birth cohorts, genders, and quantiles to implement overidentification tests. The findings show that neighborhoods affect intergenerational mobility primarily through childhood exposure, helping reconcile conflicting results in the prior literature.