Animated Lorenz Curves and Gini Coefficients
The following hyperlinks show Mathematica animations of Lorenz curves. The data are from the paper by Deininger and Squire (1996) and are available from the World Bank. The Gini coefficient is the ratio of the area between the line of complete income equality (i.e., the 45 degree line) and the Lorenz curve to the total area under the 45 degree line. Higher values of the Gini coefficient correspond to more income inequality. Complete equality of income corresponds to a Gini coefficient of zero and complete income inequality (i.e., when the wealthiest twenty percent of of the population has 100 percent of the nation's income) corresponds to a Gini coefficient of 1.0. The program calibrates a Gini coefficient "speedometer" and shows changes in the values of the Gini coefficient and the cumulative quintile shares for the time period covered in the Deininger and Squire data set. In order to produce a smooth animation, the program interpolates between the actual values of the data. The quintiles are highlighted with big dots when the actual data are being displayed. Here are twenty counties; I will add more as time and space allow.