This is, I think, a general problem with many of the studies we rely on. We learn a lot about the averages, but often I find that useless - I want to know more in-depth information about the subgroups, outliers, etc. As seen here and in the linked article, these same studies are often misinterpreted for this reason. Perhaps it's worth a post? Especially if someone is more familiar with the pertinent methodology than I.