NEW Scottish Government figures purporting to show how pupils are performing under Curriculum for Excellence should come with a health warning. Indeed, they already have. Earlier this month councils and teaching unions warned the data would be experimental, was likely to be open to interpretation, and might be used to judge schools unfairly.

What the statistics do not do is give us meaningful information about good and bad schools, or the location of effective and ineffective teachers because they are based on the subjective judgement of teachers working under different circumstances in different areas.

Those who look behind the headlines have long known that what league tables reflect, more than anything is the relative affluence of the school’s catchment. This reflects, in turn, other factors, such as stability at home, and parental support and enthusiasm for education.

Should they be used to construct league tables, they will be of little value precisely because of the lack of external benchmarks.

A school where teachers overestimate pupil performance, for example, could appear to be performing better than one where more realistic judgements were being made.

The Scottish Government itself warns that the figures should not be used to compare schools within or across local authority boundaries. But almost in the same breath, John Swinney says parents should examine the published data and use it to have a conversation with their child’s school.

The education secretary appears to wish to have his cake and eat it in this respect.

Mr Swinney says there are significant improvements required in some local authorities. It is true some schools are under-performing, but using this data to decide which ones would be unwise.

Meanwhile the lack of objectivity of the figures on pupil attainment provides Mr Swinney with a defence for his policy of introducing standardised testing in schools. Such testing might tell us more, although many parents will be happy to trust a teacher’s assessment of their child’s progress.

However, what these new figures show quite markedly is the extent of the attainment gap that exists by the time a child starts primary school. Approximately 20 per cent fewer children in the most deprived areas reach target levels in reading, writing and listening skills in primary one, than in the most affluent. This is the attainment gap the Scottish Government knows it must tackle.

In the context of the gulf in pupil achievement even at primary one level, it is worrying that other new figures show the number of children with access to a qualified teacher in the early years is falling. The earlier intervention can come to prepare children for school education, the better.

The Government is undoubtedly sincere in wanting to tackle the attainment gap in education.

But the one thing that is clear from these figures is something we should already know. Schools cannot do this alone, and unless more is done to tackle child and family poverty and inequality, they probably cannot do it at all.