"However, the increase in inequality has also magnified the difference in expected incomes between children born to low-(e.g., bottom-quintile) versus high-(top

"However, the increase in inequality has also magnified the difference in expected incomes between children born to low-(e.g., bottom-quintile) versus high-(top-quintile) income families. In this sense, mobility has fallen because a child’s income depends more heavily on her parents’ position in the income distribution today than in the past. Since the appropriate definition of inter-generational mobility depends upon one’s normative objective, we characterize the copula and marginal distributions separately in this paper." It would appear we have different normative objectives.