I wrote a piece here on Medium a few weeks ago arguing for a radical transformation of public schools, and I remember having to deal with this issue of college admissions as well.
One of the things that I was arguing was that most forms of testing need to be done away with, including the SAT and the ACT. Of course, that leaves the question of how the heck do colleges make their admission selections.
I think there are several ways of answering it. One is simply to say that colleges are blessed with bountiful resources (because the price of a college education is rising faster than just about anything ever), and they employ some of the best and brightest. They’ll be able to figure things out on their own.
Another way of looking at it is that to some extent it doesn’t even matter who they admit. Someone with a perfect GPA isn’t that different from someone with a nearly perfect GPA, and overall grades and test scores don’t give us much useful information. They’re so widely used because the logic goes “well, at least we have some kind of hard data to work with…”