Function to calculate the allocated seats according to the Hagenbach-Bischoff method in a given electoral district.

This function allocates seats to political parties in a given electoral district using the Hagenbach-Bischoff method (also known as the Droop-Hamilton ot simple quota largest-remainders rule).The method first calculates an electoral quota by dividing the total number of ballots (including blank ballots) by the number of seats to be filled plus one. Each party's ballots count is divided by this quota to determine an initial seat allocation (using the floor of the result). Remaining seats are then assigned to candidacies with the largest fractional remainders until all seats are distributed. Only parties that surpass a given ballots threshold (expressed as a proportion of total ballots) are considered for seat allocation.

Usage

hagenbach_bischoff_seats(
  candidacies,
  ballots,
  blank_ballots,
  n_seats,
  short_version = TRUE
)

Arguments

candidacies: A vector containing one of the following variable: unique codes or abbreviations of the candidacies that participated in the election.
ballots: A vector containing the absolute number of ballots (integer positive values) received by each candidacies
blank_ballots: A numerical value indicating the number of blank ballots (integer positive values).
n_seats: An integer positive value indicating the number of seats that are going to distributed for a given electoral district.
short_version: Flag to indicate whether it should be returned a short version of the data (just key variables) or not. Defaults to TRUE.

Value

A tibble with rows corresponding to each party including the following variables:

candidacies: abbrev or id of the candidacies
seats: number of seats
ballots: absolute number of ballots, just in long format
porc_seats: percentage of seats respect to the number of seats, just in long format
porc_ballots: percentage of ballots respect to party ballots (including blank ballots), just in long format
remainder: remainders of the initial division that were not selected for a seat, just in long format

Details

The purpose of this helper function is to be used in a general function, seats_allocation(), to calculate the seats distribution of every electoral district of a given election according to the Hagenbach-Bischoff method.

Author

Javier Alvarez-Liebana, Irene Bosque-Gala and David Pereiro-Pol

Examples

## Correct examples

## Seats distribution with Hamilton method for given vectors of
## candidacies and ballots without the remainder quotients

candidacies <- c("PP", "PSOE", "PODEMOS", "VOX")
ballots <- c(200, 350, 100, 200)

seats <- hagenbach_bischoff_seats(candidacies = candidacies,
                                ballots = ballots, blank_ballots = 50,
                                n_seats = 15)

# Same results in a long version (providing quotients)
seats <- hagenbach_bischoff_seats(candidacies, ballots, blank_ballots = 50,
                      n_seats = 15, short_version = FALSE)

if (FALSE) { # \dontrun{

# Incorrect examples

# Different length of candidacies and ballots

candidacies <- c("PP", "PSOE", "PODEMOS", "VOX")
ballots <- c(200, 350, 100)

seats <- hagenbach_bischoff_seats(candidacies = candidacies, ballots = ballots,
blank_ballots = 50)

# Ballots with missing values
candidacies <- c("PP", "PSOE", "PODEMOS")
ballots <- c(200, 350, NA)
seats <- hagenbach_bischoff_seats(candidacies = candidacies, ballots = ballots,
                      n_seats = 5, blank_ballots = 50,)

# Ballots with char values
candidacies <- c("PP", "PSOE", "PODEMOS")
ballots <- c("200", "350", "100")
seats <- hagenbach_bischoff_seats(candidacies = candidacies, ballots = ballots,
                      n_seats = 5, blank_ballots = 50)

# Invalid argument

candidacies <- c("PP", "PSOE", "PODEMOS", "VOX")
ballots <- c(200, 350, 100, 200)
seats <- hagenbach_bischoff_seats(candidacies = candidacies, ballots = ballots,
                      n_seats = 5, blank_ballots = 50, threshold = 0.05)

} # }