Gini coefficient

A measure of inequality or concentration, here used mainly in respect of income. The Gini coefficient is derived from the Lorenz curve (see below), which plots cumulative shares of the population, from the poorest upwards, against the cumulative share of incomes that they receive. The Gini coefficient is defined as the ratio of the area between the Lorenz curve and the total area delineated by the 45-degree line, which indicates an equal distribution of income, with everyone receiving the same amount. The Gini coefficient, therefore, varies between 0, when it would be the same as the 45-degree line and 1, when a single individual (person or household) has all the income.