View source for Hall-Tideman Index

== Definition ==
The '''Hall-Tideman''' index is a metric useful for the purpose of measuring  [[Concentration Risk]]  diversity or inequality metrics. An alternative name is Rosenbluth Index.

== Details ==
More precisely, if we have n values <math>E_i</math> summing up to a total of
:<math>
E_T = \sum^{n}_{i=1} E_{i}
</math>
and each value fraction is defined as
:<math>
w_{i} = \frac{E_i}{E_T}
</math>
Then the HTI index is defined as
:<math>
HTI = \frac{1}{2 \sum^{n}_{i=1} i w_{i} - 1}
</math>

== See Also ==
* The [[Gini Index]] is a related measure

== Implementations  ==
Open Source implementations of the HTI index are available in

* the Python library [https://github.com/open-risk/concentrationMetrics Concentration Library]


==References==
<references/>

[[Category:Univariate Concentration Index‎]]
[[Category:Risk Concentration]]

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