Ceteri Paribus, it's vastly preferable to have 1 teacher for every 30 pupils than 1 teacher for every 60 pupils.
Why would it be? If we're holding the level of education constant it obviously wouldn't be. My point is that if a teacher could convey the same amount of knowledge to a larger group you could call that being more productive. If you're not holding the amount of knowledge constant then it obviously does not make sense - but then again, productivity measures usually assume same amount of value is being provided, since they would make no sense otherwise.
I don't think you hold a degree in pedagogy, right? Because that's the reason why you don't want 60-pupil classes, right there. (Well that and, uhm you know, life quality for teachers and pupils alike).
The keyword for succes on in your average class room is diversification. You objectively can't diversify with more than 30 pupils sitting before you.
