It all come down to me to what this point touches.
When you have a test, you have something definite to prepare for. Even if you do not have dedicated mentors or well-wishing, caring teachers, you simply know there is a test that significantly improves your chances for MIT.
When you don't have a test, you have to study all the year round, do all homeworks, be active members of math, chess, or debate club all the year round and win at least province-level competitions, play an instrument at the school band, be elected the class monitor, create social equity clubs, do social service and so on.
Which path do you think will be easier for someone from an impoverished, troubled background?
Is it easier to prepare for a test for three months or be a whole different person severely constrained by your background?
Whom does no-test policies benefit? The rich White student living in a gated community, or a Black/Hispanic person living in slum-like condition?
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I have little first hand experience (was born in a middle-of-nowhere small town, but wasn’t truly poor), and a lot of second-hand experience. I know a lot of friends, acquaintances who moved up the socio-economic ladder just because test-score based admission policies existed.
The people who promote no-test policies are deluded ivory-tower dwellers detached from reality.