VoteFair representation ranking: Difference between revisions
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'''VoteFair representation ranking''' is a proportional-representation (PR) vote-counting method that uses ranked ballots and selects a candidate to win the second seat in a two-seat legislative district. The second-seat winner represents the voters who are not well-represented by the first-seat winner. Any single-winner election method that uses ranked ballots can be used for the popularity calculations.
This method can be repeated, such as to select the winners of the second and fourth seats in a five-seat district.
== Description ==
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This method ignores which political party each candidate is in, yet the winners typically are from different political parties.
== Calculation steps ==
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# Based on all the ballots, but with reduced influence for the ballots identified in step 4, identify the most popular candidate from among the remaining candidates. This candidate becomes the second-seat winner.
== Example ==
The ballots below are interpreted as if the four cities were competing for two seats in a legislature.{{Tenn_voting_example}}The [[Kemeny-Young Maximum Likelihood Method|Condorcet-Kemeny method]] identifies '''Nashville''' as the most popular candidate, meaning it wins the '''first''' seat.
VoteFair representation ranking identifies '''Memphis''' as the winner of the '''second''' seat.
The following details show how the second-seat winner is identified.
* 26% of the ballots rank the most popular candidate (Nashville) as their first choice.
* Looking at only the ballots for the remaining 74% of the voters, the most popular candidate (according to the Condorcet-Kemeny method) is Memphis.
* 58% of the ballots rank Nashville higher than Memphis.
* 58% exceeds 50% (the minimum majority) by 8% (the excess beyond majority).
* 8% divided by 58% equals 0.1379 which is used as the weight for each of the 58% of the ballots that rank Nashville higher than Memphis.
* Full weight for the ballots that do not rank Nashville higher than Memphis, combined with a weight of 0.1379 (about 14%) for the remaining ballots (that do rank Nashville higher than Memphis), identifies (according to the [[Kemeny-Young Maximum Likelihood Method|Condorcet-Kemeny method]]) the most popular candidate to be Memphis.
Memphis is declared the winner of the second seat. This candidate represents the voters who are not well-represented by the first-seat winner (Nashville).
== History ==
VoteFair representation ranking was created by Richard Fobes while writing the book titled '''Ending The Hidden Unfairness In U.S. Elections''', and is described in that book as part of the full VoteFair Ranking system.
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== External links ==
[https://github.com/cpsolver/VoteFair-ranking-cpp Open-source VoteFair Ranking software] which calculates VoteFair representation ranking results using the [[Kemeny-Young Maximum Likelihood Method|Condorcet-Kemeny method]] for popularity calculations
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