Gini Coefficient & Congressional Polarization

One of the concepts covered in the AP Comparative curriculum is the Gini coefficient which is an index of the difference between the wealthiest and the poorest in a country.  Those countries at 1.0 are the least equal and 0 is everyone with the same earnings.   Here are the Gini coefficients for countries around the world and here is a great new article on it from Vox that argues that polarization in Congress is directly related to changes in inequality.