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Schulze STV
Schulze STV is a proposed multi-winner ranked voting system designed to achieve proportional representation. It was invented by Markus Schulze, who developed the Schulze method for resolving ties using a Condorcet method. Schulze STV is similar to CPO-STV in that it compares possible winning candidate pairs and selects the Condorcet winner. It is named in analogy to the single transferable vote (STV), but only shares its aim of proportional representation, and is otherwise based on unrelated principles. The system is based on Schulze's investigations into vote management and Freeriding (voting), free riding. When a voter prefers a popular candidate, there is an advantage to first choosing a candidate who is unlikely to win ("Woodall free riding") or omitting his preferred candidate from his rankings ("Hylland free riding"). Schulze STV is designed to be as resistant to free riding as possible, without giving up the Droop proportionality criterion. Example Each voter ranks candi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ranked Voting
Ranked voting is any voting system that uses voters' Ordinal utility, rankings of candidates to choose a single winner or multiple winners. More formally, a ranked vote system depends only on voters' total order, order of preference of the candidates. Ranked voting systems vary dramatically in how preferences are tabulated and counted, which gives them Comparison of voting rules, very different properties. In instant-runoff voting (IRV) and the single transferable vote system (STV), lower preferences are used as contingencies (back-up preferences) and are only applied when all higher-ranked preferences on a ballot have been eliminated or when the vote has been cast for a candidate who has been elected and surplus votes need to be transferred. Ranked votes of this type do not suffer the problem that a marked lower preference may be used against a voter's higher marked preference. Some ranked vote systems use ranks as weights; these systems are called positional voting. In the B ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Droop Quota
In the study of Electoral system, electoral systems, the Droop quota (sometimes called the Eduard Hagenbach-Bischoff, Hagenbach-Bischoff, Britton, or Newland-Britton quota) is the Infimum, minimum number of votes a party or candidate needs to receive in a district to guarantee they will win at least one seat. Reprinted in ''Voting matters Issue 24'' (October 2007) pp. 7–46. The Droop quota is used to extend the concept of a majority to multiwinner elections, taking the place of the 50% bar in single-winner elections. Just as any candidate with more than half of all votes is guaranteed to be declared the winner in single-seat election, any candidate with more than a Droop quota's worth of votes is guaranteed to win a seat in a Multiwinner voting, multiwinner election. Besides establishing winners, the Droop quota is used to define the number of excess votes, i.e. votes not needed by a candidate who has been declared elected. In proportional electoral quota, quota-based syste ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Later-no-help Criterion
The later-no-help criterion (or LNHe, not to be confused with LNH) is a voting system criterion formulated by Douglas Woodall. The criterion is satisfied if, in any election, a voter giving an additional ranking or positive rating to a less-preferred candidate can not cause a more-preferred candidate to win. Voting systems that fail the later-no-help criterion are vulnerable to the tactical voting strategy called mischief voting, which can deny victory to a sincere Condorcet winner. Complying methods Approval, instant-runoff, highest medians, and score all satisfy the later-no-help criterion. Plurality voting satisfies it trivially (as plurality only applies to the top-ranked candidate). Descending Solid Coalitions also satisfies later-no-help. Noncomplying methods All Minimax Condorcet methods, Ranked Pairs, Schulze method, Kemeny-Young method, Copeland's method, and Nanson's method do not satisfy later-no-help. The Condorcet criterion is incompatible with later-n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Later-no-harm Criterion
Later-no-harm is a property of some Ranked voting, ranked-choice voting systems, first described by Douglas Woodall. In later-no-harm systems, increasing the rating or rank of a candidate ranked below the winner of an election cannot cause a higher-ranked candidate to lose. It is a common property in the plurality-rule family of voting systems. For example, say a group of voters ranks Alice 2nd and Bob 6th, and Alice wins the election. In the next election, Bob focuses on expanding his appeal with this group of voters, but does not manage to defeat Alice—Bob's rating increases from 6th-place to 3rd. Later-no-harm says that this increased support from Alice's voters should not allow Bob to win. Later-no-harm may be confused as implying center squeeze, since later-no-harm is a defining characteristic of Plurality voting, first-preference plurality (FPP) and Instant-runoff voting, instant-runoff voting (IRV), and descending solid coalitions (DSC), systems that have similar mechani ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Participation Criterion
The participation criterion is a voting system criterion that says candidates should never lose an election as a result of receiving too many votes in support. More formally, it says that adding more voters who prefer ''Alice'' to ''Bob'' should not cause ''Alice'' to lose the election to ''Bob''. Voting systems that fail the participation criterion exhibit the no-show paradox, where a voter is effectively disenfranchised by the electoral system because turning out to vote could make the result worse for them; such voters are sometimes referred to as having negative vote weights, particularly in the context of German constitutional law, where courts have ruled such a possibility violates the principle of one man, one vote. Positional methods and score voting satisfy the participation criterion. All deterministic voting rules that satisfy pairwise majority-rule can fail in situations involving four-way cyclic ties, though such scenarios are empirically rare, and the random ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Warren Method
The single transferable vote (STV) is a proportional representation system and ranked voting rule that elects multiple winners. Under STV, an elector's vote is initially allocated to their first-ranked candidate. Candidates are elected (''winners'') if their vote tally exceeds the electoral quota''.'' Any surplus votes (those exceeding quota) are transferred from winners to the remaining candidates (''hopefuls'') according to the surplus ballots' next usable back-up preference. The system attempts to ensure factions are represented proportionally, without the need for official party lists, by having each winner elected with roughly the same number of votes. There are several variants of the Single Transferable Vote, each with different properties. Voting When using an STV ballot, the voter ranks candidates on the ballot. For example: Some, but not all single transferable vote systems require a preference to be expressed for every candidate, or for the voter to express at lea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Instant-runoff Voting
Instant-runoff voting (IRV; ranked-choice voting (RCV), preferential voting, alternative vote) is a single-winner ranked voting election system where Sequential loser method, one or more eliminations are used to simulate Runoff (election), runoff elections. When no candidate has a majority of the votes in the first round of counting, each following round eliminates the candidate with the fewest First-preference votes, first-preferences (among the remaining candidates) and transfers their votes if possible. This continues until one candidate accumulates a majority of the votes still in play. Instant-runoff voting falls under the plurality-based voting-rule family, in that under certain conditions the candidate with the least votes is eliminated, making use of secondary rankings as contingency votes. Thus it is related to the Runoff election, two-round runoff system and the exhaustive ballot. IRV could also be seen as a single-winner equivalent of Single transferable vote, sin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
First Past The Post
First-past-the-post (FPTP)—also called choose-one, first-preference plurality (FPP), or simply plurality—is a single-winner voting rule. Voters mark one candidate as their favorite, or First-preference votes, first-preference, and the candidate with more first-preference votes than any other candidate (a Plurality (voting), ''plurality'') is elected, even if they do not have more than half of votes (a ''majority''). FPP has been used to elect part of the House of Commons of the United Kingdom, British House of Commons since the Middle Ages before spreading throughout the British Empire. Throughout the 20th century, many countries that previously used FPP have abandoned it in favor of other electoral systems, including the former British colonies of Australia and New Zealand. FPP is still De jure, officially used in the majority of U.S. state, US states for most elections. However, the combination of Partisan primary, partisan primaries and a two-party system in these jurisd ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Single Transferable Vote
The single transferable vote (STV) or proportional-ranked choice voting (P-RCV) is a multi-winner electoral system in which each voter casts a single vote in the form of a ranked ballot. Voters have the option to rank candidates, and their vote may be transferred according to alternative preferences if their preferred candidate is eliminated or elected with surplus votes, so that their vote is used to elect someone they prefer over others in the running. STV aims to approach proportional representation based on votes cast in the district where it is used, so that each vote is worth about the same as another. STV is a family of multi-winner proportional representation electoral systems. The proportionality of its results and the proportion of votes actually used to elect someone are equivalent to those produced by proportional representation election systems based on lists. STV systems can be thought of as a variation on the largest remainders method that uses candidate-based so ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Proportional Representation
Proportional representation (PR) refers to any electoral system under which subgroups of an electorate are reflected proportionately in the elected body. The concept applies mainly to political divisions (Political party, political parties) among voters. The aim of such systems is that all votes cast contribute to the result so that each representative in an assembly is mandated by a roughly equal number of voters, and therefore all votes have equal weight. Under other election systems, a bare Plurality (voting), plurality or a scant majority in a district are all that are used to elect a member or group of members. PR systems provide balanced representation to different factions, usually defined by parties, reflecting how votes were cast. Where only a choice of parties is allowed, the seats are allocated to parties in proportion to the vote tally or ''vote share'' each party receives. Exact proportionality is never achieved under PR systems, except by chance. The use of elector ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
