A recent British study has cast serious doubt on the commonly held notion that smaller class sizes can by themselves improve student achievement.
A team of researchers from the University of London studied 21,000 British students in grades 4 through 6 to determine the effects of class size on student achievement. The study by the Institute of Education at the University of London was released in December 2004.
The study was longitudinal and included baseline measures of student achievement and then followed the same students through grades 4 to 6. The study found no evidence that children in smaller classes made more progress in mathematics, English, or science, even after accounting for specific characteristics of students in small or large classrooms.
The authors explain, "statistical analysis pointed to 'a clear conclusion': there was not found to be any evidence that the size of class had any impact on progress in maths or literacy in Year 4 or Year 5. Nor was there any apparent effect on progress in maths or science in Year 6. There was 'a positive relationship' between class size and Year 6 literacy: pupils in larger classes made more progress."
Earlier class-size research by the same team found a strong relationship between class size and student achievement in literacy and math for a child�s first year of schooling.
First-Year Benefits Only
The December study did find students in smaller classrooms were more likely to be the focus of the teacher's attention and receive more direct instruction. Students in larger classrooms spent more time working in groups.
The study found no evidence that teacher characteristics often associated with teacher quality—including age, years of experience, and time at their current school—had any influence on student achievement in any subject during the years 4-6.
The researchers suggest targeting resources to support smaller classes in a student's first year, but not necessarily extending small class sizes to years 4-6.
California Results Confirmed
The British study tracks similar findings from a large-scale study of California's class-size reduction program completed last year by the RAND Corporation, which examined the standardized test scores over five years for pupils in 2,892 schools across the state. The RAND researchers found class size had little effect on student achievement in California.
These findings call into question the national trend in the United States toward smaller class sizes. Given the high cost of class-size reduction, the British study offers further support for proposals that direct scarce educational resources toward reforms shown more likely to increase student achievement in public schools.
Lisa Snell is director of education and child welfare at Reason Foundation. She formerly taught speech courses at California State University, Fullerton.