The size of schools and districts in which they are located has become a salient policy issue in recent years. While consolidation of school districts and expanding high school size were in vogue from the 1960s until recently, funding agencies are now sponsoring projects to reduce school size...

Many argue that the composition of a school or classroom-that is, the characteristics of the students themselves-affect the educational attainment of an individual student. This influence of the students in a classroom is often referred to as a peer effect. There have been few systematic studies...