A-LEVELS are so unreliable that half the candidates who ought to be awarded the top grades that would secure them places at the best universities are denied them, a new study has shown.
Prof Dylan Wiliam, of King's College, London, found that 53 per cent of those who should be awarded three A grades are given one or two grades lower, sufficient to lose them places at Oxford, Cambridge and most medical schools.
Similarly, 49 per cent of those who deserve two As and a B are downgraded, although 12 per cent are given a grade higher than they merit. Among those who ought to be awarded three Bs - the cut off point for most courses at good universities - 45 per cent are given lower grades and 22 per cent higher grades.
Prof Wiliam, who is one of the leading experts in educational assessment, said the unreliability of A-levels was caused by three factors. He said: "The first is the inconsistency of candidates - they have good days and bad days, and an individual's score on the same test can vary from day to day.
"The second is the inconsistency of markers, who sometimes disagree about the value of an answer. The third, and perhaps least acknowledged, source of unreliability is in the choice of questions. Since A-level papers are produced anew each year, candidates can be advantaged or disadvantaged by the particular choice of items in the papers they sit."
Having assigned a numerical value to each of the three factors, Prof Wiliam then ran a large-scale simulation of their impact by comparing candidates' actual grades with their "true" grades.
A true grade was the long-run average score that a candidate might be expected to achieve over repeated examinations in the subject. The findings support those who argue that A-levels need to be supplemented by other tests to identify real merit. ----------------- OTHER ARTICLES: