The effect of school size on exam performance in secondary schools

This paper investigates the relationship between school size and the exam performance of school pupils in their final year of compulsory education. Previous studies of this relationship have been seriously constrained by lack of appropriate data, but the publication of the School Performance Tables for all publicly-funded schools in England since 1992 permits the construction and testing of a multivariate model which includes school size as one of the explanatory variables. After controlling for factors such as type of school, teaching inputs and eligibility for free school meals, the partial effects of school size on exam performance are estimated. The primary result is that there is a non-linear relationship (in the form of an inverted-U) between school size that maximizes the exam performance of schools is estimated to be about 1,200 for 11-16 schools and 1,500 for 11-18 schools. These estimates are considerably higher than the current mean size of schools.