I'd like to see more data about this, as I find it interesting. I don't know. I feel pretty assured, however, that if 40% move every year, that the graph as dr

I'd like to see more data about this, as I find it interesting. I don't know. I feel pretty assured, however, that if 40% move every year, that the graph as drawn leaves out some very important details. As you noted, the interesting question (from a political viewpoint) is how much mobility is in and out of the top quintile as opposed to the bottom one. And, reasoning a bit further, if people only move among the bottom three quintiles, to them it's probably evidence that one day they might be in the top quintile, whether or not that's actually likely. This might give them a much more favorable view of lenient tax rates on the wealthy. Don't know. And from a purely political standpoint, if people feel that they are moving among the quintiles such that anybody has a chance at being in the top bunch, does it matter what the actual data is? In other words, is there a perception problem or are we trying to create one? Once again, I think you could argue this either way from the data I've seen so far.