Sets keep pupils back
The implication is that less able students are disruptive. But in my experience, one reason that "bottom" sets contain disruptive students is because schools see them as a dumping ground for students who may actually be able, but bored.
Many students in bottom sets are hard-working and keen to improve. Also, "top" sets are often populated by laid-back, under-achieving students who feel they need do no more!
There is a further danger that setting makes teachers feel they do not need to differentiate work to meet individual students' needs, when any set can, in fact, contain a wide ability range.
Teaching mixed-ability groups can be difficult, but is extremely rewarding for all. It is important not to put a ceiling on what students can achieve.
In a mixed-ability set those able, but bored students in bottom sets could show what they can do.
(Full address supplied)