Droop quotaThe Droop quota is the quota most commonly used in elections held under the single transferable vote (STV) system. It is also sometimes used in elections held under the largest remainder method of party-list proportional representation (list PR). Any candidate that receives quota is declared elected. Under some STV systems, especially those of the full-preferential voting variant, often all the winners receive the quota, but in others, of the optional-preferential voting or semi-optional preferential voting variants, if is common for as many as three winners in a district to be elected with less than quota.
Coombs' methodCoombs' method or the Coombs rule is a ranked voting system which uses a ballot counting method for ranked voting created by Clyde Coombs. The Coombs' method is the application of Coombs rule to single-winner elections, similarly to instant-runoff voting, it uses candidate elimination and redistribution of votes cast for that candidate until one candidate has a majority of votes. Each voter rank-orders all of the candidates on their ballot.
One man, one vote"One man, one vote", or "one person, one vote", expresses the principle of equal representation in voting. This slogan is used by advocates of democracy and political equality, especially with regard to electoral reforms like universal suffrage and proportional representation. The violation of equal representation in the various systems of proportional representation can be measured with the Loosemore–Hanby index, the Gallagher index, or the amount of wasted vote.
Borda countThe Borda count is a family of positional voting rules which gives each candidate, for each ballot, a number of points corresponding to the number of candidates ranked lower. In the original variant, the lowest-ranked candidate gets 0 points, the next-lowest gets 1 point, etc., and the highest-ranked candidate gets n − 1 points, where n is the number of candidates. Once all votes have been counted, the option or candidate with the most points is the winner.
Mutual majority criterionThe mutual majority criterion is a criterion used to compare voting systems. It is also known as the majority criterion for solid coalitions and the generalized majority criterion. The criterion states that if there is a subset S of the candidates, such that more than half of the voters strictly prefer every member of S to every candidate outside of S, this majority voting sincerely, the winner must come from S. This is similar to but stricter than the majority criterion, where the requirement applies only to the case that S contains a single candidate.
Electoral systemAn electoral system or voting system is a set of rules that determine how elections and referendums are conducted and how their results are determined. Electoral systems are used in politics to elect governments, while non-political elections may take place in business, non-profit organisations and informal organisations. These rules govern all aspects of the voting process: when elections occur, who is allowed to vote, who can stand as a candidate, how ballots are marked and cast, how the ballots are counted, how votes translate into the election outcome, limits on campaign spending, and other factors that can affect the result.
History and use of the single transferable voteHistorically, the single transferable vote (STV) electoral system has seen a series of relatively modest periods of usage and disusage throughout the world; however, today it is seeing increasing popularity and proposed implementation as a method of Proportional representation and a goal of electoral reform. STV has been used in many different local, regional and national electoral systems, as well as in various other types of bodies, around the world. The concept of transferable voting was first proposed by Thomas Wright Hill in 1819.
Supplementary voteThe supplementary vote (SV) is an electoral system used to elect a single winner, in which the voter ranks two of the candidates in order of preference. In an election, if no candidate receives an absolute majority of first-preference votes, then all but the two leading candidates are eliminated and there is a second count. In the second count, the votes of those who supported eliminated candidates are distributed among the two remaining candidates, so that one candidate achieves an absolute majority.
History and use of instant-runoff votingInstant-runoff voting (IRV) is a voting method used in single-seat elections with more than two candidates. Instead of voting only for a single candidate, voters in IRV elections can rank the candidates in order of preference. Ballots are initially counted for each elector's top choice, losing candidates are eliminated, and ballots for losing candidates are redistributed until one candidate is the top remaining choice of a majority of the voters.
Contingent voteThe contingent vote is an electoral system used to elect a single representative in which a candidate requires a majority of votes to win. It is a variation of instant-runoff voting (IRV). Under the contingent vote, the voter ranks the candidates in order of preference, and the first preference votes are counted. If no candidate has a majority (more than half the votes cast), then all but the two leading candidates are eliminated and the votes received by the eliminated candidates are distributed among the two remaining candidates according to voters' preferences.
