Sir: In your leading article of 18 March, you criticise the 10-level system on which the national curriculum and its assessment is based, pointing out 'the absurdity of having an academically weak 15-year-old ostensibly working at the same level as a bright seven-year-old'.

Yet on page 17 of the same edition, you report the outstanding achievements of gifted 10-year-olds in inventing sophisticated brain control systems. If a few 10-year-olds can achieve more than most average adults, why is the equivalence of attainment of bright seven-year-olds and weak 15-year-olds so absurd?

In fact, we have evidence of this equivalence from existing national tests at age seven and national pilots at 14. The current edition of Schools Update, the Department for Education journal, shows that in mathematics about 10 per cent of seven-year-olds attained at least as well as the lowest 20 per cent of 14-year-olds. The top seven-year-olds did even better.

Equally, in Reading, although no published results are yet available for 14-year-olds, 1991 pilot results show that 25 per cent of seven-year-olds attained at least as well as the lowest 10 per cent of 14-year-olds, while the best reached the average for 11-year-olds. These data hardly support the absurdity of the 10-level system.

Your leading article suggests the alternative of a different syllabus and grading system for each of the four key stages. Allowing three grades for seven-year-olds, rising to the current eight at GCSE, would require the definition of more than 20 different grades, producing an even more complex system than the current 10. If a child gained an average grade at 11 but a low one at 14, could you be sure that they had learned anything at all in between?

The 10-level system may not be perfect, but at least it provides a rough measure of the progress of each pupil, together with the average 'value added' by the school for all pupils over the key stage.

My experience in talking to those who teach mathematics all over the country suggests that the last thing they want is yet another change in the national curriculum. Aren't two changes in four years enough?

Yours sincerely,

MARGARET BROWN

Head of the School of Education

King's College

London, SE1

18 March