Tutt Library Research Guides
Inequality

Gini Index The Gini Index or the Gini coefficient is the most popular tool
used to calculate inequality by economists. 
20:20 RatioThe 20:20 ratio compares income of the top twenty percent of the
population in a given area to the bottom twenty percent of the group. See also: http://www.equalitytrust.org.uk/resources2/spiritlevel/methods 

Palma RatioThis tool compares the income of the top ten percent of the population
in a given area to the bottom forty percent. See also: http://www.cgdev.org/blog/palmavsginimeasuringpost2015inequality


Theil IndexThe Theil index is a statistic used to measure economic inequality
that borrows from information theory. 