School Size and the Distribution of Test Scores

After forty years of school consolidation, the preponderance of the evidence, including the results presented in this paper, suggest that the race to reap returns to scale and specialization in education may have come at a high price. This paper uses newly available STAR test score data from California to explore the relationship between school size and the distribution of test scores across elementary, middle, and high schools. We find that school size has a statistically significant and economically large impact on school performance. For example, the probability that an average suburban high school is dominated by low scorers rises from 47% to 71% as the school grows from 200 to 800 students per grade.