See, for example, Schmidt, F. L., & Hunter, J. (2004). General Mental Ability in the World of Work: Occupational Attainment and Job Performance, cited 1600+ times:
> The psychological construct of general mental ability (GMA), introduced by C. Spearman (1904) nearly 100 years ago, has enjoyed a resurgence of interest and attention in recent decades. This article presents the research evidence that GMA predicts both occupational level attained and performance within one’s chosen occupation and does so better than any other ability, trait, or disposition and better than job experience. The sizes of these relationships with GMA are also larger than most found in psychological research.
One main reason why you might not have seen this is that you didn't go out of your way to find it, and the mainstream publications systematically hide, distort, and often blatantly lie about the existing evidence.
Seriously who cares about a couple of IQ points?
It is a legitimate metric of *something*.
No one falls for pseudoscientific groupthink like communities of affluent, well-educated people.
Using deeply culturally and/or language biased IQ tests.
Using IQ tests that essentially just test the quality of education they received.
Sampling unrepresentative populations.
Using studies from an Apartheid state as an example of "a state without systemic racism".
Using tests that aren't IQ tests and the author explicitly say isn't equivalent and "converting" them with arbitrary systems. Literally just making up data.
Cherry picking the worst data from studies which the original study explicitly calls out as less likely to be accurate.
Every correlation vs causation mistake you can possibly make.
Just discounting every environmental factor except parental socioeconomic status.
Assuming environmental factors are a result of genetic factors (which is literally just assuming their conclusion).
Regularly citing a literally white-supremacist funded source as unbiased.
Then you weren't doing proper IQ tests. They must be administered by suitably qualified professionals and not made available for practice. You were cheating. Of course you're going to get good at a game by breaking the rules.
https://en.wikipedia.org/wiki/Environmental_racism#Impacts_o...
> It's clearly because of some more innate qualities measured by IQ.
This is an absurd statement, because even if the IQ differences exist, you are jumping to a conclusion here: that difference in IQ is innate, and not a result of racism or other external factors, with your only justification being:
> And the differences appear before school age, so it's hardly any opportunity for racism to cause it.
One of the biggest factors for childhood success is how much time your parents spend with you when you are young. If historic racism means your family is poorer, it likely means your parents can spend less time with you. Just one example of many of how this argument just doesn't hold water.