Increasing class size is one of the key variables that policy makers can use to control spending on education. But the consensus among many education researchers is that smaller classes are effective in improving student achievement. This view has led to a policy of class size reductions in a number of US states, the UK, and the Netherlands. This…

This paper uses data from the Norwegian elementary school to test whether students from disadvantaged backgrounds benefit from smaller classes. The data cover one cohort of fourth graders who have been treated in small versus large classes for a period of three years. The Norwegian class size rule of maximum 28 students is used to generate…