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...

Reaching the policy goal of improving student achieve­ment by adding resources to the school system has often proven elusive. By contrast, ample evidence indicates that central exit exams constitute an important feature of a school system’s institutional framework, which can hold students,...

We examine whether the sorting of differently achieving students into differently sized classes results in a regressive or compensatory pattern of class sizes for a sample of national school systems. Sorting effects are identified by subtracting the causal effect of class size on performance...