That sounds very tidy, but reality is not that simple. Here is a very real situation many schools face: you have 100 slots in your school. You objectively determine that X skills are needed to do well in your school. 1000 applicants demonstrate meeting X level of skills. Some of the 1000 clearly show they have skills well above X, but most of the 1000 are roughly equivalent.

Which 900 get turned away and how do you decide which?