The Gini coefficient (or Gini ratio) is a summary statistic of the Lorenz curve and a measure of inequality in a population.
BREAKING DOWN 'Gini Index'. The index is named after its developer, Corrado Gini, an Italian statistician of the early 20th century. It is typically expressed as a percentage, so a 20 coefficient would be shown as 20%. A wealthy country and a poor country can have the same Gini coefficient, even if the wealthy country has a relatively equal distribution of affluent residents and the poor country has a relatively equal distribution of cash-strapped residents. Definition: The Gini coefficient is a number between zero and one that is a measure of inequality. An example is the concentration of suppliers in a market or industry.  The Gini coefficient (or Gini ratio) is a summary statistic of the Lorenz curve and a measure of inequality in a population.  The Gini coefficient by countries (1989-2009). The Gini coefficient (also known as the Gini index or Gini ratio) is a measure of differences in income. It was developed by the Italian statistician Corrado Gini in 1912. The Gini coefficient is usually a number between 0 and 1 (or 0 to 100). 0 means a country the income is equally distributed. On the other hand, 1 means that one person owns everything but the rest own nothing. DEFINITION of 'Gini Index'. A measurement of the income distribution of a country's residents. This number, which ranges between 0 and 1 and is based on residents' net income, helps define the gap between the rich and the poor, with 0 representing perfect equality and 1 representing perfect inequality. A wealthy country and a poor country can have the same Gini coefficient, even if the wealthy country has a relatively equal distribution of affluent residents and the poor country has a relatively equal distribution of cash-strapped The Gini coefficient (also known as the Gini index or Gini ratio) (/dʒini/ jee-nee) is a measure of statistical dispersion intended to represent the income distribution of a nation's residents, and is the most commonly used measure of inequality. As another example, in a population where the lowest 50% of individuals have no income and the other 50% have equal income, the Gini coefficient is 0.5; whereas for another population where the lowest 75% of people have 25% of income and the top 25% have 75% of the income, the Gini index is also 0.5. The Gini coefficient measures the inequality among values of a frequency distribution (for example, levels of income). A Gini coefficient of zero expresses perfect equality, where all values are the same (for example, where everyone has the same income). A Gini coefficient of one (or 100%) expresses maximal inequality among values (for example, where only one person has all the income or consumption, and all others have none). As another example, in a population where the lowest 50% of individuals have no income and the other 50% have equal income, the Gini coefficient is 0.5; whereas for another population where the lowest 75% of people have 25% of income and the top 25% have 75% of the income, the Gini index is also 0.5. Distribution of family income-Gini index measures the degree of inequality in the distribution of family income in a country. The more nearly equal a country's income distribution, the lower its Gini index, e.g., a Scandinavian country with an index of 25.  The Gini index is the Gini coefficient expressed as a percentage, and is equal to the Gini coefficient multiplied by 100. (The Gini coefficient is equal to half of the relative mean difference.) The Gini coefficient is often used to measure income inequality. As with other inequality coefficients, the Gini coefficient is influenced by the granularity of the measurements. For example, five 20% quantiles (low granularity) will yield a lower Gini coefficient than twenty 5% quantiles (high granularity) taken from the same distribution.
http://www.investopedia.com/terms/g/gini-index.asp http://economics.about.com/cs/economicsglossary/g/gini.htm http://mathworld.wolfram.com/GiniCoefficient.html https://simple.wikipedia.org/wiki/Gini_coefficient http://www.investopedia.com/terms/g/gini-index.asp https://en.wikipedia.org/wiki/Gini_coefficient https://en.wikipedia.org/wiki/Gini_coefficient https://www.cia.gov/library/publications/the-world-factbook/rankorder/2172rank.html http://www3.nccu.edu.tw/~jthuang/Gini.pdf
what is a gini coefficient