But there is also evidence to suggest the exact opposite. The argument is as old as the hills and there is evidence and absolute proof on both sides. 1) I seat children by ability in English and Maths for most of these lessons, but they generally choose their seating in other subjects. Sometimes they choose in English and Maths and sometimes I group them as mixed groups. 2) Why? Because it is easier to target the teaching and guided work that way. I could hardly work with my most able children as a group if they were scattered about the room could I? If I set differentiated tasks for the children, it is easier for them to discuss the work if they are sat with children doing the same work as them. It is easier for management of work/targets/etc. I can say 'this table do this, that table do that' or 'I'll expect this from this table' if they are grouped by ability. Otherwise I'd have to call out names each and every time. 4) Errrrr none that have convinced me. I let them choose seats for lessons where differentiation is less marked because I like them to have that choice. Social reasons only. Not sure letting them choose all day every day would actually be a good idea.