The problem I have with it is that for this to be a reasonably effective strategy you should change the arbitrary metric every few years because otherwise it is likely to be hacked and has the potential to turn into a negative signal rather than positive. Essentially your false positives can dominate by "studying to the test" rather than "studying".
I'd say the same is true for college admissions too... because let's be honest, I highly doubt a randomly selected high school student is going to be significantly more or less successful than the current process. I'd imagine the simple act of applying is a strong enough natural filter to make this hypothesis much stronger (in practice, but see my prior argument)
People (and machines) are just fucking good at metric hacking. We're all familiar with Goodhart's Law, right?