From the Tax Foundation:
They seem to be describing the problem identified by Fern, and are claiming they use a model that corrects for it. The details of the model are probably in one of their research papers. What seems clear is that they haven't just taken the flawed data and ignored its shortcomings.
http://www.taxfoundation.org/files/sr139.pdf
What's interesting about the Tax Foundation is, given its conservative leaning, they oppose progressive taxation because, they say, it causes this very problem, that some states pay more than they receive, and some states pay less than they receive. They claim it's "ironic" that the blue states are getting the shaft since dem politicians favor progressive taxation.
I think their point is that dem pols who favor progressive taxation are arguing against the interests of their constituents. Of course, the inevtiable correlary is that red states pol argue against the interests of their constituents when they *oppose* progressive taxation. Fascinating.
The true "irony" here is that this "talking point" of many liberals ultimately comes from a conservative source.
- wolf