in the asian countries such as hong kong, taiwan, japan, etc, it is pretty difficult to get into medical school; most of their criteria is number based (which definitely has its downfalls) hence if you do not break a certain point on the national or college entrance exam (which used to be offered once a year), then you cannot do medicine or would have to take a year off and retake the test hoping your score will hit the threshold value. Your score might be good enough for a certain major at a certain school but not high enough for medicine, etc.
It is still very competitive in those asian countries but the type of competition is different compared to the states. it is purely a numbers game, i dont know if it's still like that; even if it has changed it is still very number biased.
The same goes for high school and middle school placements, they are placement exams to see where you go to middle/high school which means the best high school is literally the best high school in terms of numbers since no one below the threshold can attend (unless via some connections maybe? dont know).