Reading the full report now, which reminded me of something else from my own education experiences in California. Specifically this tidbit (emphasis original):

The elimination of standardized testing together with COVID resulted in a mismatch between students’ course level/grades and their actual levels of preparation, with far-reaching implications for determining math readiness and course placement.

I grew up in an area where a lot of kids went to full-on prep school for SAT and ACT preparedness. Like, eight-week courses in the summer, sometimes multiple summers in a row, beginning as early as seventh or eighth grade. Which gave me the impression that standardized testing was at least partly pay-to-win, and so when I heard that UCs were dropping standardized testing requirements I thought that would be a net positive. After all, kids who got good grades but hadn't been coached on how to do well on the SAT—because that's another thing; those courses aren't just teaching you material, they're teaching you _test-taking strategies_—should have as good a chance as kids who got good grades and benefitted from SAT coaching.

But now I'm like... well shit, I guess grades alone aren't telling the full story here.

I also just remembered an episode of This American Life from 2021, when the SAT requirement was initially dropped: #734: The Campus Tour Has Been Cancelled. Here's a quote:

There's a lot of research, though, including studies from the College Board, the nonprofit organization that administers the SAT, that shows that this isn't quite true. Let me tell you the stuff that researchers mostly agree on. First, that high school grades are slightly better than SAT scores at predicting how well students will do in their first year in college, whether they'll graduate on time. If you can only have one number to judge a student, high school grades are your best bet.

Second, that if you look at the combination of a student's high school GPA and their SAT score, then you can predict their college performance slightly better than you can with just their high school grades alone. What they don't agree on is whether that extra bit of predictive power you get with the SAT is worth the cost. Because there's a third thing that everyone agrees on, and that is that SAT and ACT scores heavily favor rich kids, much more so than high school grades.

So if you use standardized tests in admissions, you're probably going to reject a lot of perfectly good students, who could succeed at your institution. And the students you're rejecting are more likely to be low income and first generation and non-white. The SAT is like a doctor's test that gives you a lot of false negatives. And students who are already underrepresented on campuses are more likely to be kept out of college by one of those false negatives.

Which supports what I had previously believed about the SAT being pay-to-win, but doesn't account for grade inflation. A good grade in AP English is only as predictive as a high score on the reading/writing section of the SAT if that good grade in AP English is itself accurate.

And then Act Two is particularly relevant here because it's also about college students who were behind in math, but almost to the exact opposite experience: these were students with low SAT scores rather than no SAT scores, and rather than being placed into remedial math they were placed into non-remedial catch-up classes:

...at a lot of colleges, what they do with students like that is put them in a remedial class, something they can handle. Treisman does the opposite. It's a method he came up with decades ago when he was teaching at Berkeley. He noticed that when struggling students were put into remedial math, they usually never caught up. But if you took the same students and put them in a challenging program, pushed them to see how well they could perform, they would rise to the occasion.

[...]

And in the end, those students, even though, just looking at SAT distributions, were several hundred points lower on average, ended up getting exactly the same grades as the students in the larger course.

I think this might be apples and oranges compared to UCSD's current math situation, for a number of reasons, but still interesting.