More equal and poorer, or richer but more unequal?

After a hundred years of contributions, the debate about how to measure inequality is still open. We provide a brief review of the literature, showing that inequality has been assessed through a relative approach, from Gini's \citeyear{Gini} pioneering article. Analyzing historical Census data for Flint and other American cities, we observe how mean values of income in population subgroups capture the shape of the distributions of income and their comparisons state the overall situation of inequality. Namely, we adopted the approach introduced in Zenga (2007) to assess inequality. Our first findings show that prosperity is distributed unevenly across America's metropolitan areas. More interestingly, unbalanced wealth can be related to other concomitant facts (Moretti, 2013), such as population growth, income growth, unemployment rates and women participation to the labor force. Gaps between more and less educated areas were modest forty years ago, but they have become quite large nowadays (Glaser, 1994).