I am all for merit based means for determining who fills limited spots in public institutions, but the main trick is determining how the merit is ascertained.
Asa rule, the tests given are all multiple choice tests.
While choosing between A, B, C or D, DOES reveal a person's knowledge, it does not reveal ALL of a person's knowledge.
For example, if I ask, "Who was president between 1853 and 1857" as a fill in the blank question, it is unlikely most people will get the right answer.
But if I offer these choices, it becomes simple:
A. John Quincy Adams
B Henry Ashton
C. Franklin Pierce
D. Dwight David Eisenhower