This may just help to explain the "Exam Hypnosis" which is troubling many people, many of whom should know better. The reason that exams were introduced was not to assess the precise level of achievment of all pupils. It was done so that the universities did not take in students that would "let the side down" when taking "Finals". The simple matter was that there were x number of places available and so only x were to be taken in. Those x must be capable of absorbing what was given to them and so a means had to be devised to sort out the most suitable X. Exams were devised and the pass mark was set, after marking the papers, so that x passed i.e. the cream of the crop. Granted it would be unfortunate if the lowest of the x group achieved a score of 90% and the next was 89%, thus setting the pass mark at 90%, but then that, considering the variety of ability in humans, would be highly unlikely. Now I will grant that today's pantomime is not exactly like this but it is not very far removed from it. The original purpose still exists, but political expediency on the part of government (local as well as national) and on the part of the teaching and of examination boards has done nothing to make the "fog" any less dense. Why should it, it hides the truth about inefficiency in the system and its practitioners (and has done so for many many years).