Class Size, the Learning Environment and Student Outcomes

Abstract

This paper examines the effects of class size on the classroom learning environment and on student outcomes including achievement and well-being. Focusing on Madrid, we link administrative data with large-scale surveys of students, parents, and teachers, and exploit variation in class size due to a maximum class size rule. We find that class size impacts the learning environment as measured by teacher reports of classroom disruption and student reports of the classroom atmosphere. It also has some effects on teacher instructional practices. However, we find that class size has only small effects on student achievement and the effects on wellbeing are mixed. We conclude that achievement effects are minimal because smaller classes induce relatively minor changes in the classroom learning environment, and not because of compensating responses (e.g., by parents).