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 different skills within a practice session. On tests…

Beginning in 2007, the Literacy Program at the Right Age (Pacto pela Alfabetização na Idade Certa [PAIC]) in Brazil's Ceará state required municipal schools to implement a tiered, whole-school early-grade literacy intervention. This intervention was complemented by other policies to help municipalities improve student achievement. The present…