Check Fig. 4 and the discussion:
"Column 1 in Fig. 4 in the first block of
columns (corresponding to wages) shows that IQ predicts
wages, but the predictive power is small (around 1% [Adj. R squared of 0.02 in Fig. 4). Column
2 in Fig. 4 shows that self-esteem, locus of control, antisocial
behavior, and neuroticism, taken together, are more important
determinants of wages [R sq. Of .05]. Both IQ and personality remain as
important predictors in wage equations when both are included
in a regression (column 3 in Fig. 4). The fourth column in Fig. 4
shows that achievement has more predictive power than IQ and
personality alone. When IQ and personality are also included in
a regression (column 5 in Fig. 4), achievement test scores remain an important predictor of wages, and IQ and personality
also remain important predictors of wages. After controlling for
scores on achievement tests, IQ loses around 60% of its predictive power. When grades are included, instead of achievement tests, the effect of IQ becomes negligible. A similar pattern
arises across the other outcomes studied."
The achievement measure is from a test (of learned facts and skills?) at age 10 (IIUC).
Further, the paper seems to go to some effort to decompose the raw data into IQ, grades. See table 2. The correlation between iq and personality is fairly weak.