Steve Sailer has also looked at this study and has found serious problems with it. He focuses especially on a chart showing parts of the country with children who move from the bottom quintile to the top.
The chart, at a glance, is pretty absurd: West Virginia is an economic growth center, whereas Charlotte, the Triangle, and Atlanta are nowheresvilles. This explains why people have flocked to West Virginia and away from the new south.
Sailer’s note is that it seems like Raj Chetty, et al, do not really take cost of living into account. As Sailer notes, a child of two New York City residents who earn a modest amount moves to Charlotte. This person may make less than his parents but nevertheless has a higher standard of living, in that he can afford a house, car, and other accoutrements his parents would never be able to touch. Also, Sailer points out that the graph itself is a pretty good map of the percentage of black residents in an area.