> So either IQ is useful in classifying both success and failure. No, statistical relationships are not symmetric in general. You shouldn't expect equal absolu

> So either IQ is useful in classifying both success and failure. No, statistical relationships are not symmetric in general. You shouldn't expect equal absolute predictive power for events two sigma from the mean in opposite directions if the random variable doesn't have a normal distribution. IQ is normally distributed, but many obvious and conventional measures of success are clearly not. > Your second argument essentially states that "measures that don't take time into account ... don't take time into account". This isn't what I'm intending my argument to "essentially state". My second argument is just that drawing conclusions from "top line" statistics like R^2 is dangerous and potentially misleading.