Those folks who use flowery verbiage to raise questions of ‘ontology’ and ‘epistemology’ do, at least, have a kernel of a point. Education is a complex and messy process.
You only have to consider the large number of educational trials that are confounded in some way. I have written of gold-standard randomised control trials that fail to isolate the relevant factors. And this means that some questions do not have a simple answer.
When I was in primary school, the whole year group took ‘games’ at the same time. During football season we were grouped into two ability groups. The P.E. teachers never made this explicit but it was pretty obvious. I was in the lower ability group. I knew this because both teachers spent their time with the other group. My group just played a game and refereed it ourselves. It was the lads on the other half of the playing field who ended-up on the school football team.
I could be wrong but I suspect that a study of the effectiveness of this approach would have shown a positive effect for some of the boys in the upper group which was outweighed by a negative effect for those in my group. After all, nobody actually taught us how to play football. We were experiential learners.
When educators talk of the need for professional autonomy so that they can get on with the job of teaching without outside interference, I tend to think of this model. After all, my teachers obviously believed that it was fine.
Compare the ability grouping of my football lessons with the sort that’s used in Engelmann’s Direct Instruction. In this case, children are given placement tests to determine their starting level and group. A great deal of planning goes in to structuring the instruction to meet this level – Engelmann has written a famously dense book about how this is done. I don’t know, but I suspect that different group levels are generally assigned to similarly experienced and committed teachers.
The point is that ability grouping is not a single thing with a single effect. And this is why a meta-analysis of the effects of ability grouping is not likely to tell us a great deal.