That, to me, is not a problem with the exam though. It's a problem of teaching to a special case and not the general case. If you want to find fault, it's in the incentive system. But I don't see how the exam itself is the problem.
Well I won't reiterate all of 'bad education' by Bryan Caplan but to my mind exams are imperfect because:
1. Schools are not equal. It's not fair to compare students when they usually have no choice over their teachers.
2. Exams cover an arbitrary syllabus controlled by undemocratic exam boards.
3. Topics are chosen by exam boards that can be examined not by importance.
4. Students who perform poorly under stress of exam conditions are punished for it.
5. Exams serve no real purpose. Children are not chickens being graded for sale. They're at best a weak signal of aptitude.
I would much prefer exams to serve as a prerequisite of sitting a future course rather than an assessment at the end. That way teachers can actually teach rather than continuously repeat the same content.
