A very concerned member of the Governing body of a school I once worked at requested a meeting with me- could I move her son to a top set as she was very concerned that he would not achieve in the set that logically he had been placed given his Key Stage 3 results.Does putting students into ability groups make a difference? What are the implications of putting students into the ‘wrong’ ability group? Hattie reports on voluminous research from the USA that identified little effect on achievement, and serious consequences for equity. He quotes a study that found that low sets were, “...deadening, non educational environments.” A further report found that setting, “...limits students’ schooling opportunities, achievements, and life chances. Students not in the higher sets have fewer intellectual challenges, less engaging and supportive classrooms and fewer well-trained teachers.”Setting by ability seems to perform no tangible benefit in terms of achievement, and seems to result in those lucky winners of a place in a lower set receiving substandard educational experiences in a poor working environment. If a school has behavioural problems that are poorly managed then I leave it to your imagination to decide which sets attract more of the disruptive pupils.