Sir, Now that the annual controversy over A-level results is in full swing (report, August 17), it is instructive to go to the official 2007 source document, namely the tabulation of results by subject and grade. Therein are revealed such alarming discrepancies that a major overhaul of the marking systems is clearly necessary; changes could easily be made to accommodate almost all the criticism levelled by, in particular, university admissions tutors. First, there is no reason to depart from the assumption that intelligence or ability adheres to some normal distribution. Thus the percentages of candidates awarded grades A, B, C, D, E and U might be typically 10, 19, 26, 24, 14 and 7 respectively. And this distribution is almost exactly that for the subject called critical thinking. Other subjects which tally closely with this pattern are: general studies, information and communication technology, media-film-TV studies and performing-expressive arts.

The central school subjects, however, show drastically different distributions. Mathematics is the worst with 44, 21, 16, 10, 6 and 3, and is closely followed by physics, French and German. In each of these subjects the percentages decrease steadily from A to U, which is nonsensical and in no way reflects the range of candidates’ abilities.

If the examining boards were to instruct the moderators in each subject to adjust the cut-off points to ensure a normal distribution of the percentages, the differentiation which is called for would be automatically achieved, and without any need for other devices such as stars or double stars. At the same time, an increase in the difficulty of the examinations in some subjects (notably mathematics) would facilitate the requisite adjustments.

PROFESSOR SIR BRYAN THWAITES, London, W1

Sir, Surely there is a simpler solution. By providing the absolute mark, which will tell students how they did in the exam, and the rank relative to everyone else who took the exam (eg, as a percentile), which will tell the university how good one student is compared with everyone else, maybe everyone will be happy.

TOBY GARROOD, Reigate, Surrey

Sir, I would like to congratulate my fellow students who managed to achieve the A-level grades for which they have worked hard for the past two years. People always criticise the exams by saying that they become easier every year, thereby creating an impression that A levels are worthless, which may put people off carrying on with their education. The way the UK economy is moving we need as many people as possible in any form of education and this constant naysaying may be contributing to people not carrying on with any form of education.

To those who say that A levels are easy, I may agree because I achieved A grades in the subjects I took (maths and sciences), as could the few other people who achieved all A grades, but what about the high proportion at my college who didn’t (out of a group of 60 the 12 As awarded belonged to four people)?

It may just be that they appear to be getting easier because the bright students are taking more of them. More As are therefore given because bright students are being forced to take as many A levels as possible to make their college look better.

THOMAS FLETCHER, Birmingham

Sir, May I suggest a question for next year’s A-level statistics paper?

“Stating all assumptions, estimate the probability that the proportion of candidates receiving A grades will increase every year for 25 years. Compare with the given data, and comment on the validity of your calculations.”

TONY ATKINS Hungerford, Berks

Sir, I have just heard on the radio an interview with an A-level candidate. His curious mix of subjects was religious studies, chemistry and politics.

Should we be worried?

MARCUS ELLIOTT, Llandudno, Conwy

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