The Knowledge Is Power Program (KIPP) is an influential and rapidly growing nationwide network of charter schools serving primarily disadvantaged minority students. Prominent elements of KIPP's educational model include high expectations for student achievement and behavior, and a substantial increase in time in school. KIPP is being watched…

The utility of value-added estimates of teachers' effects on student test scores depends on whether they can distinguish between high- and low-productivity teachers and predict future teacher performance. This article studies the year-to-year variability in value-added measures for elementary and middle school mathematics teachers from five large…

This article proposes an unusual identification strategy to estimate the effects of disruptive students on peer behavior and academic outcomes. Because boys with names most commonly given to girls may be more prone to misbehavior as they get older, they may become differentially disruptive in school. In elementary school there is no relationship…