Alan Smithers: Why do private schools do best?

The cat is well and truly out of the bag. Even in their present form, A-levels can be fine-tuned to provide better information for universities. In trials, the exam boards have found no difficulty in creating a new grade to ease the log jam at the top.

The cat is well and truly out of the bag. Even in their present form, A-levels can be fine-tuned to provide better information for universities. In trials, the exam boards have found no difficulty in creating a new grade to ease the log jam at the top.

The leading universities are swamped with students boasting straight As. Cambridge had to turn away 5,000 last year. Distinguishing between the apparently equally qualified has become a major concern. Some universities are introducing supplementary tests, and there have been calls for the actual marks or module grades to be available. But how much better it would be to have a national examination that did its job properly. As well as a higher grade, there should also be some tougher questions so that the merely punctilious are not excessively rewarded.

Both a higher grade and more difficult questions were, in fact, Government policy in 2002, but they were suddenly dropped. The Government said that it had received advice from teachers that existing grades would be devalued. Because it is not known for listening to schools, there has to be the suspicion that there was another reason.

Perhaps the Government had got wind of what the new grade would show: the Assessment and Qualifications Alliance, the largest exam board, has found that pupils in independent schools were up to five times more likely to get the starred A grade. This cuts right across the Government's policy of putting pressure on the universities to be proportionate in their intakes from independent and maintained schools.

The result may be inconvenient, but it is no reason to block a necessary change. If the results and the policy do not fit, it could be that the policy is wrong. Encouraging universities to give preference to lower-scoring applicants would only be justified if the exams did not accurately reflect achievement.

But there is some telling validation from a recent international study of 15-year-olds - the OECD's Programme for International Assessment (Pisa). Tucked away in an appendix, and hardly discussed, is a table showing that, on the main measure of educated ability, independent schools in the UK scored best in the world. The gap between the independent and maintained schools was also the biggest in the world.

Interestingly, the UK was not alone. Independent schools did better than their state counterparts in all 16 participating countries that have them, except Japan. Furthermore, in those countries with private schools that receive more than half their core funding from the state, and which do not need to not charge fees, the results were the same: they too did better than fully maintained schools.

I hold no brief for private schools. Indeed, I feel that so long as the state compels pupils to attend school it must take responsibility for ensuring that all have access to the best possible education. But these international results are striking. What is it about independent education? Is it the abilities of the pupils they attract, parental support, the quality of the teaching, the money they receive, their freedom from state meddling or some other factor?

Pisa has produced a rich vein of evidence that is not being tapped. The OECD has largely ignored results because they do not fit in with the narrative that it is keen to develop. When the permanent secretary of the DfES was asked by a Commons select committee about the contribution of the independent schools to the UK's Pisa results, he said: "I think they are in there."

The present government has been anxious to promote itself as developing evidence-based policies. Instead of trying to cut independent schools down to size, it should be seeking to understand how it is that they are able to produce such good results, not only in this country but worldwide. The lessons learnt should be applied to maintained schools so that they offer opportunities that allow talents to flourish to the fullest. That is the way to genuine equality of opportunity, not gerrymandering the university admissions process.

The writer is director of the Centre for Education and Employment Research at the University of Liverpool

education@independent.co.uk