The accusation by senior maths examiner Jeffrey Robinson that GCSE results were "fixed" over a decade were denied yesterday by some of his fellow examiners.
A letter signed by half of the 26 examiners who worked with him on marking maths papers says his comments about a deliberate reduction of the pass mark had been "misguided".
It says: "As examiners of GCSE mathematics, we totally refute Jeffrey Robinson's thesis that pass marks have been cut over the years to boost exam grades at GCSE.
"It is misguided to suggest that because grade boundaries in GCSE mathematics are now lower than in 1989, standards have been lowered."
The writers argue that the exam is now more difficult and there was a major change in the marking system in 1994. Since then the marks have hardly changed, they say.
"In 1994 the grade C threshold was 51 (in 2001 it was 48). In 1994 the grade B threshold was 80 (in 2001 it was 77)," they say. The differences take account of the fact that the exam is now more difficult. "There has been a significant increase in the emphasis on algebra across all tiers and, in particular, an increase in the amount of manipulative algebra on Intermediate and Higher Tiers. In addition, 50 per cent of the questions now have to be answered without the use of a calculator, whereas in 1989 calculators were allowed for all questions."
Mr Robinson, one of the principal examiners with the Cambridge exam board – now the Oxford, Cambridge and RSA board (OCR) – also said that the mark for a C grade in one higher-level paper had gone down from 48 per cent to 18 per cent since 1989.
The examiners say that, under a new system of marking, only 25 per cent of the marks were now accessible to a C-grade candidate. "Thus a boundary of 18 maintains the requirement to achieve two-thirds of the marks," they add.
Similar arrangements were now in place fore the Intermediate Tier, where C-grade candidates would now find only 75 per cent of the marks accessible to them. Consequently, the 48 per cent barrier for a C grade still meant a candidate had to score nearly two-third of the marks.
One of the signatories, Bill Aldwinckle, an OCR chief examiner of maths, said: "If Jeffrey were right, he would clearly be helping to improve the examination system. As he is wrong, he does a grave disservice to the children taking GCSEs and the teachers striving to give of their best."
The letter was signed by 13 examiners; most of the rest could not be contacted because they were on holiday.
Mr Robinson made his comments on the day this year's 600,000 GCSE students received their results. He said the pass mark had been deliberately reduced over a 10-year period. "It's not opinion, it's fact," he said. "The levels at which the thresholds are drawn between grades have come down very significantly. They are effectively as much as 50 per cent lower in the case of C grades than they were in 1988."
Headteachers demanded an investigation into his claims. The general secretary of the National Association of Head Teachers, David Hart, said: "I think his allegations are outrageous and a real kick in the teeth for students and their teachers over what they have achieved. However, it is important that the examining groups do produce a report. Otherwise, the whole exam system will be devalued."
* The controversial new AS-level exams could jeopardise foreign-language learning because the exams are "much harder than other subjects" and will put students off studying a language, a leading group of linguists has warned, writes Sarah Cassidy.
The new exams in French, German and Spanish attracted 2,217 more candidates than the A-level this year and were praised by examiners as having encouraged students to broaden their studies. But only 30 more students passed because of a dramatic increase in the failure rate.
The Association for Language Learning is to ask the Education Secretary to ensure that language exams are made easier as part of the review of the controversial AS level.
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