Editing Gini coefficient (section)

==History==
The Italian statistician [[Corrado Gini]] developed the Gini coefficient and published it in his 1912 paper ''Variabilità e mutabilità'' ({{langx|en|variability and mutability}}).<ref>Gini, C. (1909). "Concentration and dependency ratios" (in Italian). English translation in ''Rivista di Politica Economica'', '''87''' (1997), 769–789.</ref><ref>{{Cite book |last=Gini |first=C |title=Variabilità e Mutuabilità. Contributo allo Studio delle Distribuzioni e delle Relazioni Statistiche |publisher=C. Cuppini |year=1912 |location=Bologna}}</ref> Building on the work of American economist [[Max O. Lorenz|Max Lorenz]], Gini proposed using the difference between the hypothetical straight line depicting perfect equality and the actual line depicting people's incomes as a measure of inequality.<ref>{{cite web |date=12 March 2015 |title=Who, What, Why: What is the Gini coefficient? |url=https://www.bbc.com/news/blogs-magazine-monitor-31847943 |access-date=30 March 2022 |website=BBC News}}</ref> In this paper, he introduced the concept of simple mean difference as a measure of variability.

He then applied the simple mean difference of observed variables to income and wealth inequality in his work ''On the measurement of concentration and variability of characters'' in 1914. Here, he presented the concentration [[ratio]], which further developed into today's Gini coefficient. Secondly, Gini observed that improving methods introduced by Lorenz, Chatelain, or Séailles could also achieve his proposed ratio.

In 1915, [[Gaetano Pietra]] introduced a geometrical interpretation between Gini's proposed ratio and between the observed area of concentration and maximum concentration. This altered version of the Gini coefficient became the most commonly used inequality index in upcoming years.<ref>{{Cite web |last=Pellegrino |first=Simone |date=2020 |title=THE GINI COEFFICIENT: ITS ORIGINS |url=https://www.bemservizi.unito.it/repec/tur/wpapnw/m70.pdf}}</ref>

According to data from the [[OECD]], the Gini coefficient was first officially used country-wide in [[Canada]] in the 1970s. Canadian index of income inequality ranged from 0.303 to 0.284 from 1976 to the end of the 1980s. The OECD has published more data on countries since the start of the 21st century. The Central European countries of [[Slovenia]], [[Czech Republic|Czechia]], and [[Slovakia]] have had the lowest inequality index of all OECD countries ever since the 2000s. [[Scandinavia]]n countries also frequently appeared at the top of the equality list in recent decades.<ref>{{Cite web |title=Inequality - Income inequality - OECD Data |url=http://data.oecd.org/inequality/income-inequality.htm |access-date=2024-04-28 |website=theOECD |language=en}}</ref>