might call middle class inequality or the size of the middle class, the gap in incomes between the 25th and 75th income, that is very highly correlated with rates of upward mobility. so our takeaway is that it seems to be something that's related to the extent to which the middle class exists and is pulling away from the poor, rather than upper tail extreme concentration of wealth. >> i don't want to leave the top 1% scott free in this because it also depends on whether they pay their taxes and their strong control over the political system. and so unless we have rectification that reflects the fact that the income as soared at the very, very top but not the taxes, we're not going to get right some of these other things. >> the thing that i'm struck most by when you look at the comparative data is how amazingly well northern europe does, particularly scandinavia, where they have a very large middle class, where there is less inequality, and where it's sort of a left-right issue is