https://github.com/polettif/proporz
Calculate seat apportionment for legislative bodies using different established methods, including biproportional apportionment.
https://github.com/polettif/proporz
apportionment apportionment-methods biproportional election-analysis
Last synced: 6 months ago
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Calculate seat apportionment for legislative bodies using different established methods, including biproportional apportionment.
- Host: GitHub
- URL: https://github.com/polettif/proporz
- Owner: polettif
- License: gpl-3.0
- Created: 2020-04-17T15:35:24.000Z (over 5 years ago)
- Default Branch: master
- Last Pushed: 2024-04-04T10:58:32.000Z (over 1 year ago)
- Last Synced: 2024-09-16T14:18:39.324Z (about 1 year ago)
- Topics: apportionment, apportionment-methods, biproportional, election-analysis
- Language: R
- Homepage: https://polettif.github.io/proporz/
- Size: 1.17 MB
- Stars: 6
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- Changelog: NEWS.md
- License: LICENSE
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README
# proporz 
Calculate seat apportionment for legislative bodies with various methods. These
methods include divisor methods (e.g. D'Hondt, Webster or Adams), largest
remainder methods and biproportional apportionment.
_Mit diesem R-Package können mittels verschiedener Sitzzuteilungsverfahren
Wählerstimmen in Abgeordnetensitze umgerechnet werden. Das Package beinhaltet
Quoten-, Divisor- und biproportionale Verfahren (Doppelproporz oder
"Doppelter Pukelsheim")._
## Installation
Install the package from CRAN:
```r
install.packages("proporz")
```
Alternatively, install the development version from Github:
```r
# install.packages("remotes")
remotes::install_github("polettif/proporz")
```
## Apportionment methods overview
### Proportional Apportionment
[`proporz()`](https://polettif.github.io/proporz/reference/proporz.html) distributes
seats proportionally for a vector of votes according to the following methods:
- **Divisor methods** ([Wikipedia](https://en.wikipedia.org/wiki/Highest_averages_method))
- D'Hondt, Jefferson, Hagenbach-Bischoff
- Sainte-Laguë, Webster
- Adams
- Dean
- Huntington-Hill
- **Largest remainder method** ([Wikipedia](https://en.wikipedia.org/wiki/Largest_remainder_method))
- Hare-Niemeyer, Hamilton, Vinton
``` r
library(proporz)
votes = c("Party A" = 651, "Party B" = 349, "Party C" = 50)
proporz(votes, n_seats = 10, method = "sainte-lague")
#> Party A Party B Party C
#> 7 3 0
proporz(votes, 10, "huntington-hill", quorum = 0.05)
#> Party A Party B Party C
#> 6 4 0
```
### Biproportional Apportionment
Biproportional apportionment ([Wikipedia](https://en.wikipedia.org/wiki/Biproportional_apportionment))
is a method to proportionally allocate seats among parties and districts.
We can use the provided [`uri2020`](https://polettif.github.io/proporz/reference/uri2020.html)
data set to illustrate biproportional apportionment with [`biproporz()`](https://polettif.github.io/proporz/reference/biproporz.html).
You need a 'votes matrix' as input which shows the number of votes for each party
(rows) and district (columns). You also need to define the number of seats per district.
``` r
(votes_matrix <- uri2020$votes_matrix)
#> Altdorf Bürglen Erstfeld Schattdorf
#> CVP 11471 2822 2309 4794
#> SPGB 11908 1606 1705 2600
#> FDP 9213 1567 946 2961
#> SVP 7756 2945 1573 3498
(district_seats <- uri2020$seats_vector)
#> Altdorf Bürglen Erstfeld Schattdorf
#> 15 7 6 9
biproporz(votes_matrix, district_seats)
#> Altdorf Bürglen Erstfeld Schattdorf
#> CVP 5 2 2 3
#> SPGB 4 1 2 2
#> FDP 3 1 1 2
#> SVP 3 3 1 2
```
You can use [`pukelsheim()`](https://polettif.github.io/proporz/reference/pukelsheim.html)
for dataframes in long format as input data. It is a wrapper for `biproporz()`. [`zug2018`](https://polettif.github.io/proporz/reference/zug2018.html) shows an actual election
result for the Canton of Zug in a dataframe. We use this data set to create input data for
`pukelsheim()`. The other parameters are set to reflect the actual election system.
``` r
# In this data set, parties are called 'lists' and districts 'entities'.
votes_df = unique(zug2018[c("list_id", "entity_id", "list_votes")])
district_seats_df = unique(zug2018[c("entity_id", "election_mandates")])
seats_df = pukelsheim(votes_df,
district_seats_df,
quorum = quorum_any(any_district = 0.05, total = 0.03),
winner_take_one = TRUE)
head(seats_df)
#> list_id entity_id list_votes seats
#> 1 2 1701 8108 2
#> 2 1 1701 2993 0
#> 3 3 1701 19389 3
#> 4 4 1701 14814 2
#> 5 5 1701 4486 1
#> 6 6 1701 15695 3
```
The [**Apportionment scenarios vignette**](https://polettif.github.io/proporz/articles/apportionment_scenarios.html)
contains more examples.
How to adapt `biproporz` for special use cases is demonstrated in the [**Modifying biproporz() vignette**](https://polettif.github.io/proporz/articles/modifying_biproporz.html).
## Shiny app
The package provides a basic Shiny app where you can calculate biproportional
apportionment on an interactive dashboard. You need to have the packages `shiny`
and `shinyMatrix` installed. [Try it out on shinyapps.io](https://polettif.shinyapps.io/proporz/)
```r
# install.packages("shiny")
# install.packages("shinyMatrix")
proporz::run_app()
```
## Function details
[**Full function reference**](https://polettif.github.io/proporz/reference/index.html)
#### Divisor methods
You can use divisor methods directly:
``` r
votes = c("Party A" = 690, "Party B" = 370, "Party C" = 210, "Party D" = 10)
# D'Hondt, Jefferson or Hagenbach-Bischoff method
divisor_floor(votes, 10)
#> Party A Party B Party C Party D
#> 6 3 1 0
# Sainte-Laguë or Webster method
divisor_round(votes, 10)
#> Party A Party B Party C Party D
#> 5 3 2 0
# Adams method
divisor_ceiling(votes, 10)
#> Party A Party B Party C Party D
#> 4 3 2 1
# Dean method
divisor_harmonic(votes, 10)
#> Party A Party B Party C Party D
#> 5 2 2 1
# Huntington-Hill method
divisor_geometric(votes, 10)
#> Party A Party B Party C Party D
#> 5 3 1 1
```
#### Largest remainder method
The largest remainder method is also accessible directly:
``` r
votes = c("I" = 16200, "II" = 47000, "III" = 12700)
# Hamilton, Hare-Niemeyer or Vinton method
largest_remainder_method(votes, 20)
#> I II III
#> 4 13 3
```
## See also
There are other R packages available that provide apportionment functions, some with
more focus on analysis. However, biproportional apportionment is missing from the
pure R packages and RBazi needs rJava with an accompanying jar.
- [RBazi](https://www.math.uni-augsburg.de/htdocs/emeriti/pukelsheim/bazi/RBazi.html): Package using rJava to access the functions of [BAZI](https://www.math.uni-augsburg.de/htdocs/emeriti/pukelsheim/bazi/welcome.html).
- [seatdist](https://github.com/jmedzihorsky/seatdist): Package for seat apportionment and disproportionality measurement.
- [disprr](https://github.com/pierzgal/disprr): Simulate election results and examine disproportionality of apportionment methods.
- [apportR](https://github.com/jalapic/apportR): Package containing various apportionment methods, with particular relevance for the problem of apportioning seats in the House of Representatives.
- [apportion](https://github.com/christopherkenny/apportion): Convert populations into integer number of seats for legislative bodies, focusing on the United States.
### Contributing
Please feel free to issue a pull request or [open an issue](https://github.com/polettif/proporz/issues/new).