enp: Effective Number of Parties

In Nicolas-Schmidt/old_esaps: Indicators of Electoral Systems and Party Systems

Description

The Effective Number of Parties (ENP) is an index developed by Laakso and Taagepera (1979) that allows to count the relevant parties in a party system. The formula consists on dividing one over the sum of the squares of the proportions (votes or seats) that the parties obtain in an electoral instance.

Usage

enp(esapsObject, summary = FALSE)

Arguments

esapsObject	An esaps class object. Function: esaps_object.
summary	Summary of the data by country, by default it is FALSE.

Examples

votes <- list(data.frame(country = rep("ARG", 3),
                         year = c(1995, 2000, 2005),
                         party_A = c(40,10,20),
                         party_B = c(35,20,40),
                         party_C = c(25,70,40)),
              data.frame(country = rep("URY", 4),
                         year = c(1995, 2000, 2005, 2010),
                         party_A = c(30,30,20,20),
                         party_B = c(30,50,40, 30),
                         party_C = c(30,10,30, 25),
                         party_D = c(10,10,10,25)),
              data.frame(country = rep("BRA", 2),
                         year = c(1993, 1998),
                         party_A = c(30, 55),
                         party_B = c(70, 45)))

votes <- esaps_object(dataset = votes, name.country = "country", name.year = "year")
en_party <- enp(votes, summary = TRUE)

Nicolas-Schmidt/old_esaps documentation built on May 17, 2019, 3:13 a.m.