—“Curt, I’d like to ask about your break down of class. It seems based on IQ and income level is that a correct assessment?”—
Um… well, I use genetic, social, occupational, and economic classes – even though they overlap a great deal as horizontal classes.
And I use the three specializations in means of coercion as vertical classes.
But since there is such a high correlation between genetic classes and all other horizontal classes, unless I say otherwise, I am generally referring to genetic classes.
And genetic class refers to a portfolio of fitnesses that include IQ as well as personality, morphology, and health.
So with that qualification, I think I would say that just as IQ a high predictor in life, it is not the only predictor. But for purpose of general argument it is as good a rule of thumb as any other.