Setting pupils by ability, one of the most widely-trailed parts of last week's white paper, has few benefits, a study funded by the Department for Education and Skills has concluded.
There is no evidence that streamed or set classes produce, on average, higher performance than mixed-ability classes, said the report. It also found that setting pupils is already widespread, particularly in maths.
The white paper calls for more grouping and setting of students by ability and says "grouping students can help to build motivation, social skills and independence; and most importantly can raise standards because pupils are better engaged in their own learning". The study, by the universities of Brighton, Sussex, Cambridge and London university's institute of education, agrees that grouping children within classes - common in primary schools - may have the potential to raise standards, but it stresses that there is no known way of grouping pupils which will benefit all students.
It says the debate between setting and mixed-ability teaching has become polarised and does not reflect what happens in schools where a wide range of ways of grouping pupils is used.
In secondaries, where many schools assign pupils to classes for particular subjects based on ability, there is no academic advantage for most pupils in being set according to ability or taught in a mixed-ability class.
Gifted and talented pupils are believed to make more progress in a separate ability group. But for pupils in low-ability groups, the process could mean poorer teaching and a limited curriculum leading to pupils making less progress and becoming demotivated. The review concluded: "There are no significant differences between setting and mixed-ability teaching in overall attainment ... but ... low-achieving pupils show more progress in mixed-ability classes and high-achieving pupils show more progress in set classes."
Three of the studies which made up part of the review noted that middle-class parents supported ability grouping.
In primary schools about a quarter of maths classes and a seventh of English classes are set according to ability, but setting barely exists in other curricular subjects.
Professor Peter Kutnick, of Brighton university, said that helping children work effectively in groups did help. "Even within a high-ability set class there is still a range of abilities," he said. "Teachers often decide not to differentiate so the children at the low end of the upper ability tend to be left behind.
"Just putting pupils in groups and telling them to work is not effective.
Teachers need to work with children to develop sensitivity and trust towards each other. "Where teachers have training in group work and children learn to support each other, be sensitive and communicate well to solve problems jointly, those children do better academically."
The Effects of Pupil Grouping: Literature Review by Professor Peter Kutnick, Brighton university, Professor Judy Sebba, Sussex university, Professor Peter Blatchford, London university's institute of education and Professor Maurice Galton, Cambridge university and Jo Thorp, Brighton university (with Helen MacIntyre and Lucia Berdondini) is at www.dfes.gov.ukresearch For more information see www.workingwithothers.org