Intraschool Variation in Class Size

Economists attempting to explain the widening of the black-white wage gap in the late 1970's by differences in school quality have been faced with the problem that recent data reveal virtually no gap in the quality of schools attended by blacks and whites using a variety of measures. In this paper, we reexamine racial differences in school quality by considering the effects of using the pupil-teacher ratio, rather than the school's average class size,in an education production function since the pupil-teacher ratio is a rough proxy, at best. We find that while the pupil-teacher ratio and average class size are correlated, the pupil-teacher ratio is systematically less than or equal to the average class size. Part of the difference is due to intraschool allocation of teachers to classes. While the pupil-teacher ratio shows no black-white differences in class size, measures of the school's average class size suggest blacks are in larger classes. Also, the two measures lead to differing estimates of the role of class size in an education production function. We also conclude that school level measures may obscure important within-school variation in class size due to the small class s