[mcpackieh]

'Disproven' is too strong, it's trivially true at the extreme edge cases. But smaller class sizes fail to eliminate all the performance gaps between schools, so the idea of class size (and/or school funding) being the explanation for all school performance gaps has been disproven. Particularly, smaller class sizes can't eliminate a performance gap caused by different conditions at home, whether students bully each other for trying to learn, etc.

But there's really no question that a small class where teachers can know each individual student is better than a large class of hundreds of students or more, where the teachers can't realistically remember who is who.