A British study found children in small primary classes did no better in English and math. In Year 6 (sixth grade?), reading scores were higher for students in larger classes. London University researchers followed “thousands of pupils in their fourth, fifth and sixth years of schooling.”
However, a long-term follow-up of a Tennessee study of small class size found significant benefits for children who spent three or four years in classes of 13 to 17 students.
It’s believed the greatest benefit of small classes comes in kindergarten and first grade. Perhaps the English students started small classes too late.