I never heard of anyone suggesting only SAT. What I heard instead (and what's happening in real life) is universities ditching the SAT. Countless universities d

I never heard of anyone suggesting only SAT. What I heard instead (and what's happening in real life) is universities ditching the SAT. Countless universities did that (e.g. those in the U. California system). The stated reason is equity, but it's often followed by "it's redundant anyway". Well, it's not redundant. And this study shows that. Now you are saying that the SAT does not explain much of the freshmen year GPA. But that could be (and it probably is) a consequence of the fact that colleges have different standards. The SAT could have 100% prediction power, like the Oracle of Delphi, if the colleges have different standards the correlation between SAT and GPA will be low. A second effect is at play here, the binning effect. If you have two variables X and Y that are highly correlated (let's say rho = 99%),and then you split the observations in bins based on X, then the correlation of X and Y for each can be very low. They could be arbitrarily close to zero. Just give it a try. Finally, prediction power beyond the first year. Why would colleges need that? They need quantitative metrics to determine who would perform well once they come in. After that, it's their duty to educate and nurture those students. If they can't do that, and the final outcome is some form of lottery ticket, that's on them, not on the SAT.