先发制人是美国著名的学前干预政策。这篇文章是一篇经典的政策评估文章，发表在五大经济学杂志之一的《美国经济评论》上。我将把本文的主要内容总结成PDF格式，然后在视频中具体总结本文及其实证方法。
这是它的摘要：”在收入动态的小组研究中使用了专门收集的成人数据
这是它的摘要：”Specially collected data on adults in the Panel Study of Income Dynamics are used
to provide evidence on the longer-term effects of Head Start, an early intervention
program for poor preschool-age children. Whites who attended Head Start are,
relative to their siblings who did not, significantly more likely to complete high
school, attend college, and possibly have higher earnings in their early twenties.
African-Americans who participated in Head Start are less likely to have been
booked or charged with a crime. There is some evidence of positive spillovers from
older Head Start children to their younger siblings. (JEL J24, 138)“