Ginikerroin

Ginikerroin, Finnish term for the Gini coefficient, is a statistical measure used to quantify inequality in a distribution, most commonly income or wealth. It summarizes how evenly or unevenly a population’s resources are distributed. The coefficient ranges from 0 to 1 (often expressed as 0% to 100%). A value of 0 indicates perfect equality, where everyone has the same income, while a value of 1 indicates maximal inequality, where a single individual holds all income. In practice, real-world values fall between these extremes.

Calculation and interpretation: The measure derives from the Lorenz curve, which plots the cumulative share of income against the cumulative share of people. The Gini coefficient is the area between the Lorenz curve and the line of equality, divided by the total area under the line of equality. For a dataset of n observations with incomes x1 ≤ x2 ≤ … ≤ xn and average μ, a common discrete formula is G = (1 / (n μ)) × sum_{i=1}^n (2i − n − 1) x_i. Several equivalent formulas exist. The coefficient is widely used to compare inequality across countries, regions, or time.

Applications and limitations: Ginikerroin can be calculated for income, consumption, or wealth distributions. Comparisons can be influenced by data sources, whether measurements are gross or net, population coverage, and whether the unit is households or individuals. It is a single summary statistic and does not indicate where or why inequality occurs, nor does it capture changes in different parts of the distribution if the Lorenz curve remains similar. Therefore, it is commonly complemented by other measures such as the Palma ratio or Theil index.