Students in some countries do far better on international achievement tests than students in other countries. Is this all due to differences in what students bring with them to school - socio-economic background, cultural factors, and the like? Or do school systems make a difference? This essay...

Students in some countries do far better on international achievement tests than students in other countries. Is this all due to differences in what students bring with them to school – socio-economic background, cultural factors, and the like? Or do school systems make a difference? This...

Recent evidence suggests a positive effect of the quantity of instruction on student achievement. In this paper, I focus on the interaction between the quantity and the quality of instruction. Using international TIMSS data, I exploit within-student between-subject variation. I find that on...

How does class size in compulsory school affect peoples' long run education and earnings? We use maximum class size rules and Norwegian administrative registries allowing us to observe outcomes up to age 48. We do not find any indication of beneficial effects of class size reduction in...

We report results from a large-scale, pre-registered randomized field experiment in 159 Norwegian schools over four years. The intervention includes students aged 7-9 and consists of pulling students from their regular mathematics classes into small, homogenous groups for mathematics instruction...