GrofmanModInv: Calculates an inverted modified Grofman index of...

In polrep: Calculate Political Representation Scores

Calculates an inverted modified Grofman index of proportionality

Description

Calculates an inverted modified Grofman index of proportionality based on a population vector and a vector for the representatives

Usage

GrofmanModInv(Z,R)

Arguments

Z	Population vector
R	Vector for the representatives

Details

The order of the groups in he population vector and the vector for the representatives needs to be the same. If there are groups A, B, C in the population, both vectors need to cover their proportion in the same order.

The inverted modified Grofman index is 1 minus the sum the absolute differences between the proportion of the population and representatives in each group. A division by the effective number of groups in the population is applied. To divide by the effective number of groups among the representatives, use GrofmanInv.

Value

A single score given the population and representatives

Author(s)

Didier Ruedin

References

Taagepera, R., and B. Grofman. Mapping the indices of seats-votes disproportionality and inter-election volatility. Party Politics 9, no. 6 (2003): 659-77.

See Also

Grofman, GrofmanInv, GrofmanMod

polrep documentation built on Jan. 5, 2024, 3:01 a.m.