Developed in 1912 by Corrado Gini, the Gini coefficient (or Gini index) measures income distribution among the residents of a specified geography, such as a country, a state, or a census tract. A Gini coefficient of 1 means all income belongs to a single individual, while a coefficient of 0 reflects a perfectly even distribution. The measure is most often used to look at income inequality.
See the Gini index below in various geographies for the United States. Simply click on any of the large maps to enter the interactive map environment and zoom to your own location. Geography is changed by clicking on the drop down on the right side of the map room.