Later-no-help Criterion
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Later-no-help Criterion
The later-no-help criterion 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 Two-round system, Single transferable vote (including traditional forms of Instant Runoff Voting and Contingent vote), Approval voting, Borda count, Range voting, Bucklin voting, and Majority Judgment satisfy the later-no-help criterion. When a voter is allowed to choose only one preferred candidate, as in plurality voting, later-no-help can either be considered satisfied (as the voter's later preferences can not help their chosen candidate) or not applicable. Noncomplying methods All Minimax Condorcet methods (i ...
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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 ...
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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 ...
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Later-no-harm Criterion
The later-no-harm criterion is a voting system criterion formulated by Douglas Woodall. Woodall defined the criterion as " ding a later preference to a ballot should not harm any candidate already listed." For example, a ranked voting method in which a voter adding a 3rd preference could reduce the likelihood of their 1st preference being selected, fails later-no-harm. Voting systems that fail the later-no-harm criterion are vulnerable to the tactical voting strategies called bullet voting and burying, which can deny victory to a sincere Condorcet winner. However, the fact that all cardinal voting methods fail the later-no-harm criterion is essential to their favoring consensus options (broad, moderate support) over majoritarian options (narrow, strong support). Complying methods Two-round system, Single transferable vote, Instant Runoff Voting, Contingent vote, Minimax Condorcet (a pairwise opposition variant which does not satisfy the Condorcet Criterion), and Descending S ...
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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 ...
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Condorcet Criterion
An electoral system satisfies the Condorcet winner criterion () if it always chooses the Condorcet winner when one exists. The candidate who wins a majority of the vote in every head-to-head election against each of the other candidatesthat is, a candidate preferred by more voters than any othersis the Condorcet winner, although Condorcet winners do not exist in all cases. It is sometimes simply referred to as the "Condorcet criterion", though it is very different from the "Condorcet loser criterion". Any voting method conforming to the Condorcet winner criterion is known as a Condorcet method. The Condorcet winner is the person who would win a two-candidate election against each of the other candidates in a plurality vote. For a set of candidates, the Condorcet winner is always the same regardless of the voting system in question, and can be discovered by using pairwise counting on voters' ranked preferences. A Condorcet winner will not always exist in a given set of votes, which ...
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Descending Acquiescing Coalitions
The discography of the experimental music group Psychic TV consists of over 100 full-length albums, over 15 compilation albums and over 30 singles and EPs. Studio albums *'' Force the Hand of Chance'' (LP, cassette) (1982) *'' Themes'' (LP) (1982) *''Dreams Less Sweet'' (LP, cassette) (1983) *'' Pagan Day'' (LP, 12" picture disc) (1984) *''Those Who Do Not'' (2x12") (1984) *''Descending'' (1984) *''Mouth of the Night'' (CD, LP, 12" picture disc) (1985) *'' Themes 2'' (LP) (1985) *''Themes 3'' (LP) (1986) *''The Magickal Mystery D Tour EP'' (1986) *''Allegory and Self'' (CD, LP, 12" picture disc) (1988) *'' Jack the Tab – Acid Tablets Volume One'' (CD, LP, 12" picture disc) (1988) *'' Tekno Acid Beat'' (CD, LP) (1988) *''Kondole'' (CD) (1989) *''At Stockholm (CD) (1990)'' *'' Jack the Tab/Tekno Acid Beat'' (2xCD, 2X12") (1990) *''Towards Thee Infinite Beat'' (CD, 12", cassette) (1990) *''Beyond Thee Infinite Beat'' (CD, 2x12", cassette) (1990) *''Direction ov Travel'' (CD) (1991 ...
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Nanson's Method
The Borda count electoral system can be combined with an instant-runoff procedure to create hybrid election methods that are called Nanson method and Baldwin method (also called Total Vote Runoff or TVR). Both methods are designed to satisfy the Condorcet criterion, and allow for incomplete ballots and equal rankings. Nanson method The Nanson method is based on the original work of the mathematician Edward J. Nanson in 1882. Nanson's method eliminates those choices from a Borda count tally that are at or below the average Borda count score, then the ballots are retallied as if the remaining candidates were exclusively on the ballot. This process is repeated if necessary until a single winner remains. If a Condorcet winner exists, they will be elected. If not, (there is a Condorcet cycle) then the preference with the smallest majority will be eliminated. Nanson's method can be adapted to handle incomplete ballots (including " plumping") and equal rankings ("bracketing"), tho ...
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Copeland's Method
Copeland's method is a ranked voting method based on a scoring system of pairwise "wins", "losses", and "ties". The method has a long history: * Ramon Llull described the system in 1299, so it is sometimes referred to as "Llull's method" * The Marquis de Condorcet described a similar system in the 1780s, so the method could be referred to as "Condorcet's method", but instead other systems were subsequently devised that choose the Condorcet winner. * Arthur Herbert Copeland described the system in the 1950s, so it has been frequently been called "Copeland's method". (unpublished). Each voter is asked to rank candidates in order of preference. A candidate A is said to have majority preference over another candidate B if more voters prefer A to B than prefer B to A; if the numbers are equal then there is a preference tie. The Copeland score for a candidate is the number of other candidates over whom they have a majority preference ''plus'' half the number of candidates with whom t ...
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Schulze Method
The Schulze method () is an electoral system developed in 1997 by Markus Schulze that selects a single winner using votes that express preferences. The method can also be used to create a sorted list of winners. The Schulze method is also known as Schwartz Sequential dropping (SSD), cloneproof Schwartz sequential dropping (CSSD), the beatpath method, beatpath winner, path voting, and path winner. The Schulze method is a Condorcet method, which means that if there is a candidate who is preferred by a majority over every other candidate in pairwise comparisons, then this candidate will be the winner when the Schulze method is applied. The output of the Schulze method gives an ordering of candidates. Therefore, if several positions are available, the method can be used for this purpose without modification, by letting the ''k'' top-ranked candidates win the ''k'' available seats. Furthermore, for proportional representation elections, a single transferable vote (STV) variant known as ...
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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 ...
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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 ...
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