> This is one mistake, and the danger of using IQ as anything more than a trend indicator. Employers don't need 'people with an IQ over ${ARBITRARY_CUTOFF}'. They need 'people who can do X and Y'. Even exams which focus on pass/fail of an aptitude rather than excellence show little 'racial' variance in general.

The scientific literature is very clear on this point--IQ is predictive of job performance. If you need people who can do X & Y, IQ is the best predictor[0] of whether a given individual will be able to do X & Y.

> And IQs over 100 quickly stop having significant predictive power for mental abilities other than IQ tests.

I would love to see a source for this claim.

> The numbers in that paragraph also seem entirely fantastical to me. It basically claims not only that there are IQ differences between the "races", but that they are huge.

The numbers in the paragraph are partly due to differences in IQ, and partly due to the nature of distributions. IIRC, Murray claims a mean IQ difference of ~15 points between 'Africans' and 'Asians'. Here's an image[0] of two distributions with an equivalent mean difference. Note how, the farther you get from the center, the greater the proportion of red:black. At 1 standard deviation, the ratio is 3:2, at 2sds, the ratio is 4:1!

> Even granted that there are such huge differences in IQ between various "racial" groups, the social justice response won't change - we need to focus on eliminating the social and environmental causes at the root of these differences.

The point of this conversation is that, if these differences are due to genetics, then no amount of 'eliminating causes' will address the root cause of these differences.

> Murray could claim that the differences are genetic, but I am very curious what is the scientific methodology by which he defines these groups - how much genetic testing did he do determine whether one particular person is 'European', 'African', 'Latin', or 'Asian'? What genes in particular was he looking for that make someone European? (For that matter, are Italians and Spanish people "European" or "Latin"?? Is Eva Longoria, whose family came from Spain to America with a royal land grant 400 years ago "European" or "Latin"?).

All the data he uses relies on self-reporting of race. Self-reporting is always how race is assigned. Self-reporting is how we know that certain minorities are 'underrepresented' in certain jobs--folks self-report their race when hired. It's the same way we know that there are differences in incomes and in educational achievement between races--self-reporting. You can doubt the veracity of self-reporting of race, but that doubt would have to apply to all data with a racial dimension. And, anyway, if race was some sort of fuzzy, meaningless construct (as you appear to be implying), then we would expect there to be little correlation between race and anything, let alone IQ. And yet the data show these differences (according to Murray).

Longoria would be 'Latin' (Hispanic). The whole race vs. ethnicity thing is weird, but he explains it well in the book.

[0]https://www.jstor.org/stable/20182140
[1]https://tamino.files.wordpress.com/2015/07/shiftmean.jpeg