[xiler]

> And I would also expect that social mobility would decrease as an economy "matures". If you're in a developing country seeing 7-10% GDP growth, then you'd hope mobility is higher than an economy growing at 1-2% per year.

They address that in the paper:

> Higher GDP growth rates do not substantially increase the number of children who earn more than their parents because a large fraction of GDP goes to a small number of high income earners today. To see why absolute mobility is insensitive to the growth rate when growth is distributed unequally, consider the extreme case in which one child obtains all of the increase in GDP. In this case, higher GDP growth rates would have no effect on absolute mobility. More generally, GDP growth has larger effects on absolute mobility when growth is spread more broadly, allowing more children to achieve higher living standards than their parents. Higher GDP growth and a broader distribution of growth have a multiplicative effect on absolute mobility: Absolute mobility is highest when GDP growth rates are high and growth is spread broadly across the distribution.

https://science.sciencemag.org/content/356/6336/398.full