In certain fields such as ecology, inverse Simpson's index formula_41 is used to quantify diversity, and this should not be confused with the Simpson index formula_42. These indicators are related to Gini. The inverse Simpson index increases with diversity, unlike Simpson index and Gini coefficient which decrease with diversity. The Simpson index is in the range 1, where 0 means maximum and 1 means minimum diversity (or heterogeneity). Since diversity indices typically increase with increasing heterogeneity, Simpson index is often transformed into inverse Simpson, or using the complement formula_43, known as Gini-Simpson Index.