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…

This study examined the effect of class sizes on differences in the trajectories of elementary school students' long-term Japanese language achievement by analyzing panel data composed of standardized achievement test scores at five points from around the end of first grade to around the end of fifth grade. The data for 103 schools, 162 classes,…

Purpose: This study explored the relation between therapy group size and language outcomes for children receiving school-based language therapy through an implementation science lens. Method: Data for the current study were gathered as part of the Speech-Language Therapy Experiences in Public Schools study. Participants included 273…

In an effort to reduce viral transmission, many schools are planning to reduce class size if they have not reduced it already. Yet the effect of class size on transmission is unknown. To determine whether smaller classes reduce school absence, especially when community disease prevalence is high, we merge data from the Project STAR randomized…

In an effort to reduce viral transmission, many schools are planning to reduce class size if they have not reduced it already. Yet the effect of class size on transmission is unknown. To determine whether smaller classes reduce school absence, especially when community disease prevalence is high, we merge data from the Project STAR randomized…

Increasing class size is one of the key variables that policy makers can use to control spending on education. But the consensus among many education researchers is that smaller classes are effective in improving student achievement. This view has led to a policy of class size reductions in a number of US states, the UK, and the Netherlands. This…

Background: Class size reduction (CSR) is an enduring school reform undertaken in an effort to improve academic achievement and has been widely encouraged in the United States. Supporters of CSR often cite the positive contemporaneous and carryover effects of Project STAR. Much has been discussed regarding the robustness of the contemporaneous…

Class size and student achievement have been debated for decades. The vast amount of research on this topic is either conflicting or inconclusive. There are large and small scale studies that support both sides of this dilemma (Achilles, Nye, Boyd-Zaharias, Fulton, & Cain, 1994; Glass & Smith, 1979; Slavin, 1989). Class size reduction is a…

In a four-year study of the effect of class size on pupil outcomes in a sample of 36 primary schools in Hong Kong, it has been found that there are few positive differences in attainment between classes set at less than 25 pupils and those of normal size averaging 38. Three cohorts of pupils were studied. In Cohort 1 pupils spent 3 years in small…

This brief summarizes findings on class size from over 25 years of work on the Tennessee Student Teacher Achievement Ratio (STAR) randomized, longitudinal experiment, and other Class-Size Reduction (CSR) studies throughout the United States, Australia, Hong Kong, Sweden, Great Britain, and elsewhere. The brief concludes with recommendations. The…

Does reduced class size cause higher academic achievement for both Black and other students in reading, mathematics, listening, and word recognition skills? Do Black students benefit more than other students from reduced class size? Does the magnitude of the minority advantages vary significantly across schools? This article addresses the causal…

Background/Context: One important question to educational research is whether teachers can influence student achievement over time. This question is related to the durability of teacher effects on student achievement in successive grades. The research evidence about teacher effects on student achievement has been somewhat mixed. Some education…

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…

Many studies have shown the benefits of smaller class sizes--including random experiments like the Student Teacher Achievement Ratio Project conducted in 79 elementary schools in Tennessee, which assigned children to either small or regular-size classes, as well as large-scale analyses of small and large classrooms that have occurred naturally.…