# concentration: Electoral Concentration In electoral: Allocating Seats Methods and Party System Scores

## Description

Electoral concentration is a measure of the accumulation of votes in the two most voted parties of a given territorial unit. It is the cumulative fraction of valid votes obtained by the two most voted parties in a given election (Consejo Nacional Electoral - Ecuador, 2014).

The formula is:

concentration = p1 + p2

where p1 is the vote/seat proportion for the most voted party, and p2 is the vote/seat proportion for the second most voted party. Thus, it requires elections with at least 2 parties.

The index is a number positive up to 1. A value of 1 means maximum concentration (p1 + p2 = 1, i.e. pi = 0 for i = 3,4...)

Developed by Jorge Albuja Delgado ([email protected]).

## Usage

 `1` ```concentration(votes) ```

## Arguments

 `votes` greater-than-1-length vector of number o proportion of votes/seats per party

## Value

A single numeric with concentration value in the interval (0, 1].

## Examples

 `1` ```concentration(votes = c(100, 150, 60)) ```

electoral documentation built on Oct. 25, 2018, 9:06 a.m.