Intraschool Variation in Class Size: Patterns and Implications

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 sizes for compensatory education and a kind of aggregation bias results. Not only are blacks in schools with larger average class sizes but they are also in larger classes within schools, conditional on class type. The intraschool class size patterns suggest that using within-school variation in education production functions is not a good solution to aggregation problems due to non-random assignment of students to different sized classes. But once the selection problem has been addressed,smaller classes at the 8th grade lead to larger test score gains from 8th to 10th grade and differences in class size can explain approximately 15% of the black-white gap in educational achievement.

The Effects of Class Size on the Long Run Growth in Reading Abilities and Early Adult Outcomes in the Christchurch Health and Development Study

This paper utilizes the feature of the CHDS data from New Zealand that children are sampled for extremely long individual histories of their class size experiences as well as their scholastic and early labor market outcomes. Our interest is to explore the full set of empirical implications of the recent experimental evidence on class size effects on student achievement from the United States in Project STAR for observational data. We argue that one implication of Project STAR is that only persistent class size reduction policies may have detectable effects, and so the longitudinal aspect of CHDS is necessary to detect class size effects. We account for the observational nature of the CHDS (in that children were not randomly assigned to different class sizes) by examining the long-run trends in test score growth, rather than levels. Consistent with the experimental evidence, we find statistically and economically significant effects of children being assigned to persistently smaller classes on both childhood test score growth as well as on early adult outcomes. Our analysis points the way towards the unification of experimental and observational evidence on class size effects, as well as highlighting several possible pitfalls in the analysis of observational data on this topic.School Quality; Value-Added Model; Experimental Evidence

Inside the 'Black Box' of Project STAR: Estimation of Peer Effects Using Experimental Data

The credible identification of endogenous peer group effects -- i.e. social multiplier or feedback effects -- has long eluded social scientists. We argue that such effects are most credibly identified by a randomly assigned social program which operates at differing intensities within and between peer groups. The data we use are from Project STAR, a class size reduction experiment conducted in Tennessee elementary schools. In these data, classes were comprised of varying fractions of students who had previously been exposed to the Small class treatment, creating class groupings of varying experimentally induced quality. We use this variation in class group quality to estimate the spillover effect. We find that when allowance is made for this 'feedback' effect of prior exposure to the Small class treatment, the peer effects account for much of the total experimental effects in the later grades, and the direct class size effects are rendered substantially smaller.Peer Effects; Data with a Group Structure; Organization of Schooling; Experimental Evidence

Race and School Quality Since Brown vs. Board of Education

This paper presents evidence on the quality of schooling by race and ethnic origin in the United States. Although substantial racial segregation across schools exists, the average pupil-teacher ratio is approximately the same for black and white students. Hispanic students, however, on average have 10 percent more students per teacher. Relative to whites, blacks and Hispanics are less likely to use computers at school and at work. The implications of these differences in school quality for labor market outcomes are examined. We conclude by examining reasons for the increase in the black-white earnings gap since the mid-1970s.

The Effects of Class Size on the Long Run Growth in Reading Abilities and Early Adult Outcomes in the Christchurch Health and Development Study

This paper utilizes the feature of the CHDS data from New Zealand that children are sampled for extremely long individual histories of their class size experiences as well as their scholastic and early labor market outcomes. Our interest is to explore the full set of empirical implications of the recent experimental evidence on class size effects on student achievement from the United States in Project STAR for observational data. We argue that one implication of Project STAR is that only persistent class size reduction policies may have detectable effects, and so the longitudinal aspect of CHDS is necessary to detect class size effects. We account for the observational nature of the CHDS (in that children were not randomly assigned to different class sizes) by examining the long-run trends in test score growth, rather than levels. Consistent with the experimental evidence, we find statistically and economically significant effects of children being assigned to persistently smaller classes on both childhood test score growth as well as on early adult outcomes. Our analysis points the way towards the unification of experimental and observational evidence on class size effects, as well as highlighting several possible pitfalls in the analysis of observational data on this topic

Inside the ‘Black Box’ of Project STAR: Estimation of Peer Effects Using Experimental Data

The credible identification of endogenous peer group effects -- i.e. social multiplier or feedback effects -- has long eluded social scientists. We argue that such effects are most credibly identified by a randomly assigned social program which operates at differing intensities within and between peer groups. The data we use are from Project STAR, a class size reduction experiment conducted in Tennessee elementary schools. In these data, classes were comprised of varying fractions of students who had previously been exposed to the Small class treatment, creating class groupings of varying experimentally induced quality. We use this variation in class group quality to estimate the spillover effect. We find that when allowance is made for this 'feedback' effect of prior exposure to the Small class treatment, the peer effects account for much of the total experimental effects in the later grades, and the direct class size effects are rendered substantially smaller