<p>@ManfromUncle - Exactly, the study is limited in scope, and I don’t think the authors claim otherwise. I did look at the study in somewhat more detail, but certainly not a thorough or complete reading. And yes, I am quite capable and educated in research, statistics, methodology, etc. My own take is that people that get higher GPA’s in high school are more likely to go to college (and my own take on that is that these people are more organized, more intelligent, and more motivated on average), complete college, and thus of course earn more money. As I have said several times, this is hardly breaking news. The only value I see here is that the study provides some quantitative data to the scale of that gap in earnings, and actually it is smaller than I would have thought. To that limited degree, the study, to me, has some value.</p>
<p>People are getting far more exorcized about this than needs be. A simple study, mostly confirming what common sense and experience tells us, with a small twist of a slightly surprising (to me) smaller earnings gap than expected. And you are right, only for that rather narrow, yet very important, age slice.</p>