At my school in England, once or twice a year the best/worst students in each class were swapped with the class above/below, based on the teachers' decisions. I had this for maths and French.
I completely messed up a French test on purpose, so the teacher had an excuse to put me in the class below. We really didn't like each other, and I did much better being in the top 25% of the middle class, rather than the bottom 25% of the top class.
British teachers call splitting up a year by ability for all subjects "streaming", and just for some classes "setting", and searching with both terms shows there's plenty of debate on the merits of each (or neither) method at all ages. Since I left the UK, it looks like politicians have been trying to get involved.
I completely messed up a French test on purpose, so the teacher had an excuse to put me in the class below. We really didn't like each other, and I did much better being in the top 25% of the middle class, rather than the bottom 25% of the top class.
British teachers call splitting up a year by ability for all subjects "streaming", and just for some classes "setting", and searching with both terms shows there's plenty of debate on the merits of each (or neither) method at all ages. Since I left the UK, it looks like politicians have been trying to get involved.