The Gini Index, or Gini coefficient, is a statistical measure of distribution that is often used to track economic inequality. It measures how wealth is distributed in a given population. The output is a value between 0 and 1.
Higher values mean greater inequality. A Gini value of 0 means a perfectly equal society, where everyone's income is the same. A value of 1, on the other hand, represents perfect inequality—a society in which only one person or group has all the wealth. The Gini Index data in this article is reported by the American Community Survey.