The problem with this type of analysis is there is always a motivation behind it.<p>This kind of analysis is deployed as an argument that it is okay that wealthier kids get better-funded schools with more opportunities to advance.  Because (supposedly) the analysis proved the poorer kids are being held back by genetics, not the inequalities of the system.<p>And this kind of analysis is used to justify racism.  Since race is genetic, and socioeconomic outcome is correlated to genetics, then SES correlation with race is to be expected.  So (the racist argument goes) racism is rational and justified, and efforts to counter it are pointless.<p>The linked article does not go this far, true.  But ask, what is the motivation for making the arguments he is making?