This study used systematic observation to test the direct and moderating effects of class size on children's momentary behavioural engagement in learning. Data were collected with 632 children (50.6% girls) in 121 classrooms in 92 schools recruited into the Children's School Lives national cohort study of Irish primary schooling. The Observational…

Class size reduction policies have been widely implemented around the world in recent years. However, findings about the effects of class size on student achievement have been mixed. This study examines class size effects on fourth-grade mathematics achievement in 14 European countries using data from TIMSS (Trends in International Mathematics and…

Schools across the United States are facing budgetary pressures on a scale not seen in generations. Times of fiscal exigency force policymakers and education practitioners to pay more attention to the return on various categories of public investment in education. The sizes of the classes in which students are educated are often a focus of these…

Results from experimental and nonexperimental studies have shown that teachers differ in their effectiveness. In addition, evidence from nonexperimental studies has indicated that teacher effects last for 3 years in elementary grades. This study uses data from Project STAR and its follow-up study, the Lasting Benefits Study, to examine whether…

This article addresses three questions: Does reduced class size cause higher academic achievement in reading, mathematics, listening, and word recognition skills? If it does, how large are these effects? Does the magnitude of such effects vary significantly across schools? The authors analyze data from Tennessee's Student/Teacher Achievement Ratio…

This paper addresses the relationship between class size and student-teacher interactions as an explanation for effects of class size on achievement. Observations were conducted in kindergarten and Grade 1 classes from 46 Dutch primary schools in order to address the effect of class size on the amount and type of student-teacher interactions. The…

The findings on the social distribution of the immediate and lasting benefits of small classes have been mixed. We used data from Project STAR and the Lasting Benefits Study to examine the long-term effects of small classes on the achievement gap in mathematics, reading, and science scores (Stanford Achievement Test). The results consistently…

The California class size reduction program provided schools with cash rewards for K-3 classes of 20 or fewer students. I show how program rules made it possible for schools to save money by using mixed-grade classes to meet class size reduction obligations while maintaining larger average class sizes. I also show that this smoothing of students…

Small classes in the elementary grades have been shown to boost students' academic performance. However, researchers continue to seek a consistent, integrated explanation of "why" small classes have positive effects. This article forwards the hypothesis that when class sizes are reduced, major changes occur in students' engagement in the…

Despite evidence from the USA that children in small classes of less than 20 do better academically there is still a vociferous debate about the effects of class size differences in schools, and considerable gaps in our understanding of the effects of class size differences. This article summarises results from the most complete UK analysis to…