One recent re-analysis of the Tennessee STAR project (which randomly assigned some kids to smaller classes) shows that smaller classes don't reduce the achievement gap:
A Northwestern University study investigating the effects of class size on the achievement gap between high and low academic achievers suggests that high achievers benefit more from small classes than low achievers, especially at the kindergarten and first grade levels.
"While decreasing class size may increase achievement on average for all types of students, it does not appear to reduce the achievement gap within a class," said Spyros Konstantopoulos, assistant professor at Northwestern's School of Education and Social Policy.
Konstantopoulos' study, which appears in the March issue of Elementary School Journal, questions commonly held assumptions about class size and the academic achievement gap -- one of the most debated and perplexing issues in education today.
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Konstantopoulos found that that the children who already were high achievers were the primary beneficiaries of the extra attention smaller classes afforded.
"It is likely that high achievers are more engaged in learning opportunities and take advantage of the teaching practices that take place in smaller classes, or that they create opportunities for their own learning in smaller classes," said Konstantoupoulos.
"Given that class size reduction is an intervention that benefits all students, it's tempting to expect that it also will reduce the achievement gap," he added. Previous research, however, has provided weak or no evidence that class reduction benefited lower-achieving students more than others. The Northwestern study underscores that research.