I would add that the procedure of using a plain multivariate regression to draw quasi-causal conclusions is definitely wrong because of the fallacy of controlli

I would add that the procedure of using a plain multivariate regression to draw quasi-causal conclusions is definitely wrong because of the fallacy of controlling for intermediate variables (IQ causes education, so an estimate of the form log(wages) ~ IQ + education is not estimating what you think it is estimating and a small estimate for IQ is expected), and they seem to be very casual about the measurement error though they know it's driving a lot of the results: "For example, in the NLSY79, IQ is a better predictor of log wages than personality, but in the BCS and the MIDUS data, personality measures are better predictors. The better and more comprehensive personality measures in the BCS and the MIDUS data compared with those available in the NLSY data likely explain why personality is more predictive of outcomes in those data." Not to mention that correlations with income tend to increase when you look at multi-year averages and unbin & untruncate the single-year income data to boot. If they did a more meaningful SEM (like Education ~ IQ, Wages ~ IQ + Education), with correction for all the measurement error, I would expect that, in line with the rest of the literature (I have collected some links on the topic in http://www.gwern.net/Embryo%20selection#iqincome-bibliography http://www.gwern.net/Embryo%20selection#iqincome-bibliograph... ), they would find that IQ outpredicts the rest of the variables, followed by whatever corresponds to Conscientiousness.