schools allocate weaker students to smaller classes and offer more remedial tutoring. Notably, parents provide more support to … exploits school-starting-age rules in 34 countries, capturing achievement variation that arises because younger children … typically underperform their older peers. Parents respond to lower performance by providing additional homework help, while …

assignment of students to classrooms and find positive peer effects on test scores. With rich data on nineteen potential … mechanisms, we then estimate how effects on attitudes, parents, and teachers could drive these results. Higher-achieving peers …