0 Professor John Hattie's latest paper shows again that reducing class size has a relatively small effect on outcomes and that choice of school is even less important. Whereas the variability of teaching within schools has a much bigger impact on student achievement.
Based on 662 studies, which sampled the equivalent of around three million students, the data showed that lowering the number of pupils in the classroom adds about four months of teaching per year. The difference between choosing either a private or a state school adds only one month of teaching per year.
By contrast, focusing on getting a teacher with the best expertise has a much bigger effect. If the choice is between teachers within the school, the quality of the teaching can add almost two years per year to a child's education.
Professor Hattie said: "For two kids of the same ability it almost doesn't matter which school they go to, but it matters who teaches them. The choice is not either about large or small classes or whether it is an academy or not. Instead, parents should be comparing class size with teachers' expertise."
Hattie advises that too much attention is often paid to parents' desire to choose which school their child attends, when the evidence shows that the classroom they attend is more important. Policymakers should therefore focus their efforts on reducing within-school variability of teacher effectiveness, as opposed to simply offering more school choice to parents.
