Dundee has challenged the arguments for setting in the first two years of secondary school, rejecting the Inspectorate's advice on class organisation spelt out last autumn in Achievement for All and the Scottish Secretary's latest recommendation in the education White Paper published three weeks ago.
Education officials in the city cite a general lack of research evidence to justify the change from mixed-ability teaching and warn of organisational difficulties.
Gillian Dugdale, depute director of education, maintains that claims about the lack of attainment and slower pace of progress in S1 and S2 are based on "selective and incomplete" comparisons, and emphasises that improvements in attainment in S4-S6 are related to the growing effectiveness of teaching in the first two years.
Ms Dugdale says the Inspectorate has excluded potentially more significant factors in attainment, including pupil and teacher expectations and attitudes and the different rates at which pupils develop and mature.
She adds: "Weaknesses of mixed-ability learning and teaching are overstated without supporting evidence. The claim that mixed ability restricts opportunities for direct teaching and that too much time is consumed managing resources and explaining what is done is not true in most classrooms and these problems are not self-evidently resolved by setting."
A report to councillors says it is "a sweeping generalisation" to argue that mixed-ability teaching produces a culture of low achievement. Many schools have used such methods to embrace earlier advice from HMI on improving the "ethos of achievement".
Ms Dugdale says: "The merits of setting are overstated. While setting may be appropriate in certain situations, all schools should be alert to the inherent dangers in setting which can lead to the same negative effects as streaming. "
Setting was likely to present organisational problems in small secondaries and departments and friction over which pupils were allocated to certain sets. Ms Dugdale also warns of a growing divergence in learning attainment and of the difficulties in moving between sets. Dundee backs a range of teaching approaches, including grouping pupils by ability within one class under a general mixed-ability format. Setting may be appropriate "in certain circumstances".