Uh, it’s not. The research O’Brien cites refers to the chance that someone whose parents are in the bottom 20% of the income distribution can rise to the top 20% of the distribution.
Stipulating that the data in the study is complete and accurate, and that everything in the analysis is legit — well, why is there a bright spot on the resulting map in the vicinity of Tuscaloosa, Alabama, but no corresponding bright spot near Athens, Georgia? Why does rural Arkansas look like a beacon of upward mobility, while the bustling economies of Atlanta and Charlotte produce no such effect?
Most of all, why does the map referenced by O’Brien show that impoverished Appalachia offers more opportunity for advancement than any of the more prosperous surrounding flatlands?
To use a social science term: Your data is obviously fucked up.
When I first ran across this a couple of days ago, it didn’t pass my smell test right from the git-go. But I’ve been battling a nasty cold all this week, and was just too lazy to dig into it to see where they’d buried the bodies. Luckily, Stacy McCain did a better job than I probably would have done, and confirmed that, even with a cold, my sniffer was working just fine.