>The more interesting data would measure how fluid are the populations of income deciles between generations or even within a single lifespan.
Even that wouldn't be too interesting to me. What if the society we live in just distributes a lot of income on the basis of luck? We would appear to be a highly fluid society but from the perspective of any individual there would still be little you could do to advance. Some really interesting data would be to take a child's income across life and regress it by some of the luckiest things you can have, parental income level / parent hours spent reading to child before 8 years old / attendance of pre-k / quality of child's high school. Then we could see not just fluidity but independent effortful movement in the economy.
Even that wouldn't be too interesting to me. What if the society we live in just distributes a lot of income on the basis of luck? We would appear to be a highly fluid society but from the perspective of any individual there would still be little you could do to advance. Some really interesting data would be to take a child's income across life and regress it by some of the luckiest things you can have, parental income level / parent hours spent reading to child before 8 years old / attendance of pre-k / quality of child's high school. Then we could see not just fluidity but independent effortful movement in the economy.