This study reports the findings from a year-long randomized evaluation assessing the impact of assigning 62 classrooms in Nigeria to receive either blocked or interleaved math problem sets. Blocked practice sessions focused on a single skill at a time. Interleaved problem sets alternated between...

This paper assesses whether delays in obtaining permanent residency status can explain recent declines in the share of Chinese and Indian PhD graduates from US STEM programs who remain in the US after their studies. We find that newly-binding limits on permanent visas for those from China and...

This paper experimentally investigates the effect of gender-based affirmative action (AA) on performance in the lab, focusing on a tournament environment. The tournament is based on GRE math questions commonly used in graduate school admission, and at which women are known to perform worse on...

There has been a proliferation of websites that warehouse instructional materials designed to be taught by teachers in a traditional classroom. While this new technology has revolutionized how most teachers plan their lessons, the potential benefits of this innovation are unknown. To present...

We study an intensive math instruction policy that assigned low-skilled 9th graders to an algebra course that doubled instructional time, altered peer composition and emphasized problem solving skills. A regression discontinuity design shows substantial positive impacts of double-dose algebra on...

We present a model of stereotypes in which a decision maker assessing a group recalls only that group's most representative or distinctive types relative to other groups. Because stereotypes highlight differences between groups, and neglect likely common types, they are especially inaccurate...

Many economists believe knowledge production generates positive spillovers among knowledge producers. The available evidence, however, is mixed. We argue that spillovers can exist along three dimensions (idea, geographic, and collaboration space). To isolate the key channel through which...

This paper examines the effects of policies that increase the number of students who take the first course in algebra in 8th grade, rather than waiting until 9th grade. Extending previous research that focused on the Charlotte-Mecklenberg school system, we use data for the 10 largest districts...