The GINI coefficient and segregation on a continuous variable

Purpose – The Gini coefficient is a widely used measure of income inequality. It has also been used as a segregation measure, but only in the case of binary variables, for example race or gender. We develop a general version of the Gini Segregation Index (Gs) that can accommodate either continuous or binary variables, and discuss its relationship to existing measures. Methodology – The Gini Index of Segregation is developed graphically and derived mathematically, illustrating the relationship between Gini's use in segregation and inequality applications. Findings – Using the Public Use Microdata Sample for 25 U.S. metropolitan areas from the 2000 Census, we illustrate the calculation of the index and show that it is highly correlated with an existing measure of economic segregation. Originality – This paper develops and illustrates a measure of segregation for continuous variables, a task for which there are few alternative measures.