One practical use of research on IQ and personality is deciding how much to invest in a child's education. If it is clear he is going to be an average student, public school might be all he needs. If an ordinary school is not going to maximize his potential, spending a lot of money for a better one makes sense. I never attended anything but public schools and was rarely challenged. (Let's not even get into the fact that my mind was conditioned into a naturalistic view of the world from the earliest grades. That's a subject for another post.)
We all know that IQ is highly predictive of academic success, but HBD-ers should not fall into the trap of believing it is everything. Personality traits matter as well.
This new study published in Personality and Individual Differences reports that conscientiousness, agreeableness, openness, and grit (or perserverance) all predict academic achievement. The reasons seems obvious enough except for agreeableness. I suspect that disagreeable students are punished academically for being less cooperative.
UPDATE: I forgot to list negative emotionality. It lowers academic achievement. Being controlled by anger, depression, and anxiety, I'm sure, impairs function in many areas.