> Isn't this just "I'm OK with error bars in the direction I favor", which happens to be equity? Unless you're saying you're OK with accepting the tests we have, with error bars that might err too far on the side of "other racial/cultural groups are less intelligent".
Not exactly: Precisely, I'd prefer error bars that are equally sized for everyone, instead of error bars that differ based on cultural factors, especially if we aren't capable of acknowledging the cultural disparity in distribution of those error bars (and IME, people generally aren't).
In other words, if you have a test that has an error of X when comparing 2 white kids, and an error of X when comparing two black kids, but an error of 3X when comparing a white kid to a black kid, you don't have a test with a precision of X, you have a test with an error of 3X (or worse: you have a test with a precision of X, but that consistently biases in favor of one group).
If on the other hand we have a test that has errors of 2X, but has that across cultural boundaries, that's a better test and we should use it instead. This is because the errors are randomly distributed across the population (so anyone has the same chance of being positively or negatively impacted by the test's imprecision) instead of culturally tied.
If we're willing to acknowledge the different distributions of error, then maybe we can make do, but consistent problems with things like affirmative action suggest that, at a macro level, we aren't.