<p>@tk21769 :</p>
<p>There’s really no contradiction if you think it through. Hoxby doesn’t control enough (just test scores and GPA). When Dale&Kreuger add the controls of getting in to an elite school (or even having the motivation & confidence to apply), the difference disappears (except for those from URM/disadvantaged backgrounds, and I’d add immigrants as well). The effect that Hersch sees can also be explained by those from URM/disadvantaged backgrounds not being inculcated with upper-middle class mores or having those networks.</p>