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Condorcet Loser Criterion
In single-winner voting system theory, the Condorcet loser criterion (CLC) is a measure for differentiating voting systems. It implies the majority loser criterion but does not imply the Condorcet winner criterion. A voting system complying with the Condorcet loser criterion will never allow a ''Condorcet loser'' to win. A Condorcet loser is a candidate who can be defeated in a head-to-head competition against each other candidate.https://arxiv.org/pdf/1801.05911 "We say that an alternative is a Condorcet loser if it would be defeated by every other alternative in a kind of one-on-one contest that takes place in a sequential pairwise voting with a fixed agenda4.– Condorcet loser criterion (CLC), ..we say that a social choice procedure satisfies the Condorcet loser criterion (CLC) provided that a Condorcet loser is never among the social choices." (Not all elections will have a Condorcet loser since it is possible for three or more candidates to be mutually defeatable in diffe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Voting System
An 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. Political electoral systems are defined by constitutions and electoral laws, are typically conducted by election commissions, and can use multiple types of elections for different offices. Some electoral systems elect a single winner to a unique position, such as prime minister, president or governor, while others elect multiple winners, such as memb ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
STAR Voting
STAR voting is an electoral system for single-seat elections. Variations also exist for multi-winner and proportional representation elections. The name (an allusion to star ratings) stands for "Score then Automatic Runoff", referring to the fact that this system is a combination of score voting, to pick two finalists with the highest total scores, followed by a "virtual runoff" in which the finalist who is preferred on more ballots wins. It is a type of cardinal voting electoral system. Method In STAR, voters are given a score, or ratings ballot, on which each voter scores every candidate with a number from 0 to 5, with 0 representing "worst" and 5 representing "best." The scores for each candidate are then summed, and the two highest-scored candidates are selected as finalists. In the automatic-runoff round, the finalist who was given a higher score on a greater number of ballots is selected as the winner. Usage The concept was first proposed in October 2014 by Mark Froh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Smith Criterion
The Smith criterion (sometimes generalized Condorcet criterion, but this can have other meanings) is a voting systems criterion defined such that it's satisfied when a voting system always elects a candidate that is in the Smith set, which is the smallest non-empty subset of the candidates such that every candidate in the subset is majority-preferred over every candidate not in the subset. (A candidate X is said to be majority-preferred over another candidate Y if, in a one-on-one competition between X & Y, the number of voters who prefer X over Y exceeds the number of voters who prefer Y over X.) The Smith set is named for mathematician John H Smith, whose version of the Condorcet criterion is actually stronger than that defined above for social welfare functions. Benjamin Ward was probably the first to write about this set, which he called the "majority set". The Smith set is also called the ''top cycle''. The term ''top cycle'' may be somewhat misleading, however, since the S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Minimax Condorcet
In voting systems, the Minimax Condorcet method (often referred to as "the Minimax method") is one of several Condorcet methods used for tabulating votes and determining a winner when using ranked voting in a single-winner election. It is sometimes referred to as the Simpson–Kramer method, and the successive reversal method. Minimax selects as the winner the candidate whose greatest pairwise defeat is smaller than the greatest pairwise defeat of any other candidate: or, put another way, "the only candidate whose support never drops below percent" in any pairwise contest. Description of the method The Minimax Condorcet method selects the candidate for whom the greatest pairwise score for another candidate against him or her is the least such score among all candidates. Formal definition Formally, let \operatorname(X,Y) denote the pairwise score for X against Y. Then the candidate, W selected by minimax (aka the winner) is given by: : W = \arg \min_X \left( \max_Y \operator ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bucklin Voting
Bucklin voting is a class of voting methods that can be used for single-member and multi-member districts. As in highest median rules like the majority judgment, the Bucklin winner will be one of the candidates with the highest median ranking or rating. It is named after its original promoter, the Georgist politician James W. Bucklin of Grand Junction, Colorado, and is also known as the Grand Junction system. Voting process Bucklin rules varied, but here is a typical example: Voters are allowed rank preference ballots (first, second, third, etc.). First choice votes are first counted. If one candidate has a majority, that candidate wins. Otherwise the second choices are added to the first choices. Again, if a candidate with a majority vote is found, the winner is the candidate with the most votes accumulated. Lower rankings are added as needed. A majority is determined based on the number of valid ballots. Since, after the first round, there may be more votes cast than vo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Range Voting
Score voting or range voting is an electoral system for single-seat elections, in which voters give each candidate a score, the scores are added (or averaged), and the candidate with the highest total is elected. It has been described by various other names including evaluative voting, utilitarian voting, interval measure voting, the point system, ratings summation, 0-99 voting, average voting and utility voting. It is a type of cardinal voting electoral system, and aims to implement the utilitarian social choice rule. Score voting should be distinguished from positional voting systems, such as the Borda count: in score voting, each voter is free to give any score to any candidate; in positional voting, the score that each voter gives to each candidate is uniquely determined by the candidate's rank in the voter's ballot. Usage Political use Combined approval voting, a 3-rank form of score voting, is used to determine which candidates represent the parties in Latvia's Saei ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Approval Voting
Approval voting is an electoral system in which voters can select many candidates instead of selecting only one candidate. Description Approval voting ballots show a list of the options of candidates running. Approval voting lets each voter indicate support for one or more candidates. Final tallies show how many votes each candidate received, and the winner is the candidate with the most support. Effect on elections Approval voting advocates Steven Brams and Dudley R. Herschbach predict that approval voting should increase voter participation, prevent minor-party candidates from being spoilers, and reduce negative campaigning. FairVote published a position paper arguing that approval voting has three flaws that undercut it as a method of voting and political vehicle (the group instead advocates for Instant-runoff voting). They argue that it can result in the defeat of a candidate who would win an absolute majority in a plurality election, can allow a candidate to win who ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Contingent Vote
The 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. This ensures that one candidate achieves a majority and is declared elected. The contingent vote differs from IRV which allows for many rounds of counting, eliminating only one weakest candidate each round. IRV allows a small chance the candidate outside the top two can still win. The contingent vote can also be considered a compressed form of the two-round system (runoff system), in which both 'rounds' occur witho ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plurality Voting
Plurality voting refers to electoral systems in which a candidate, or candidates, who poll more than any other counterpart (that is, receive a plurality), are elected. In systems based on single-member districts, it elects just one member per district and may also be referred to as first-past-the-post (FPTP), single-member plurality (SMP/SMDP), single-choice voting (an imprecise term as non-plurality voting systems may also use a single choice), simple plurality or relative majority (as opposed to an ''absolute majorit''y, where more than half of votes is needed, this is called ''majority voting''). A system which elects multiple winners elected at once with the plurality rule, such as one based on multi-seat districts, is referred to as plurality block voting. Plurality voting is distinguished from ''majority voting'', in which a winning candidate must receive an absolute majority of votes: more than half of all votes (more than all other candidates combined if each voter ha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Majority Loser Criterion
The majority loser criterion is a criterion to evaluate single-winner voting systems. The criterion states that if a majority of voters prefers every other candidate over a given candidate, then that candidate must not win. Either of the Condorcet loser criterion or the mutual majority criterion implies the majority loser criterion. However, the Condorcet criterion does not imply the majority loser criterion, since the minimax method satisfies the Condorcet but not the majority loser criterion. Also, the majority criterion is logically independent from the majority loser criterion, since the plurality rule satisfies the majority but not the majority loser criterion, and the anti-plurality rule satisfies the majority loser but not the majority criterion. There is no positional scoring rule which satisfies both the majority and the majority loser criterion, but several non-positional rules, including many Condorcet rules, do satisfy both criteria. Methods that comply with this ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ranked Pairs
Ranked pairs (sometimes abbreviated "RP") or the Tideman method is an electoral system developed in 1987 by Nicolaus Tideman that selects a single winner using votes that express preferences. The ranked-pairs procedure can also be used to create a sorted list of winners. If there is a candidate who is preferred over the other candidates, when compared in turn with each of the others, the ranked-pairs procedure guarantees that candidate will win. Because of this property, the ranked-pairs procedure complies with the Condorcet winner criterion (and is a Condorcet method). Procedure The ranked-pairs procedure operates as follows: # Tally the vote count comparing each pair of candidates, and determine the winner of each pair (provided there is not a tie) # Sort (rank) each pair, by strength of victory, from largest first to smallest last.In fact, there are different ways how the ''strength of a victory'' is measured. This article uses Tideman's original method based on margins of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
