Gini Index
From Open Risk Manual
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Contents
Definition
For the purpose of measuring name, sector or geographic concentration, the Gini Index (also Gini coefficient) is an index defined in terms of the Lorentz curve of the exposures.
Details
More precisely, if we have n exposures summing up to a total exposure of
and the fractional exposures are defined as
Then the Gini index is defined as the area under the Lorenz curve which is geometrically reduced to
Usage
None
Variations
None
Issues and Challenges
NB: Sometimes the formula appears also with the opposite sign!
Implementations
Open Source implementations of the Gini index are available in
- the R package Ineq
- the Python library Concentration Library
See Also
None