We study the impact on learning of a child's rank in the classroom using a unique experiment from Ecuador. Within each school, students were randomly assigned to classrooms in every grade between kindergarten and 6th grade.Therefore, two students with the same ability can have different...

We study the determinants of math achievement among children in early elementary school using data from a unique experiment in which children were randomly assigned to classrooms within schools for four consecutive grades. As a result, each child in our sample was exposed to four separate,...