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Tideman's Alternative Method
Tideman's Alternative Methods, including Alternative Smith and Alternative Schwartz, are two electoral systems developed by Nicolaus Tideman which select a single winner using votes that express preferences. These methods can also create a sorted list of winners. These methods are Smith- and Schwartz-efficient, respectively, and thus are Condorcet methods. They operate by using instant-runoff voting for cycle resolution. Procedure Tideman's Alternative procedure is as follows: # Identify the Smith or Schwartz set. # If the set consists of one candidate, elect that candidate. # Eliminate all candidates outside the set and redistribute ballots. # Eliminate the plurality loser. # Repeat the procedure. To create a sorted list of preferred candidates, select a winner, remove that winner from the list of candidates, and repeat. Features Tideman's Alternative Methods are easier to understand than other methods, such as Ranked Pairs and Schulze, owing to the simplicity of exp ...
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Electoral Systems
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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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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Independence Of Smith-dominated Alternatives
Independence of Smith-dominated alternatives (ISDA, also known as Smith-IIA or Weak independence of irrelevant alternatives) is a voting system criterion defined such that its satisfaction by a voting system occurs when the selection of the winner is independent of candidates who are not within the Smith set. A simple way to describe it is that if a voting system is ISDA, then whenever you can partition the candidates into group ''A'' and group ''B'' such that each candidate in group ''A'' is preferred over each candidate in group ''B'', you can eliminate all candidates of group ''B'' without changing the outcome of the election. Any election method that is independent of Smith-dominated alternatives automatically satisfies the Smith criterion (because all candidates not in the Smith set can be eliminated without changing the result, implying that the winner was someone in the Smith set), and all criteria implied by it, notably the Condorcet criterion and the mutual majority crit ...
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Independence Of Irrelevant Alternatives
The independence of irrelevant alternatives (IIA), also known as binary independence or the independence axiom, is an axiom of decision theory and various social sciences. The term is used in different connotation in several contexts. Although it always attempts to provide an account of rational individual behavior or aggregation of individual preferences, the exact formulation differs widely in both language and exact content. Perhaps the easiest way to understand the axiom is how it pertains to casting a ballot. There the axiom says that if Charlie (the irrelevant alternative) enters a race between Alice and Bob, with Alice (leader) liked better than Bob (runner-up), then the individual voter who likes Charlie less than Alice will not switch his vote from Alice to Bob. Because of this, a violation of IIA is commonly referred to as the "spoiler effect": support for Charlie "spoils" the election for Alice, while it "logically" should not have. After all, Alice ''was'' liked better t ...
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Burlington Mayoral Election, 2009
The 2009 Burlington mayoral election was held in March 2009 for the city of Burlington, Vermont. A few years earlier, the city had switched to holding mayoral elections every three years (e.g. the 1997 election, the 2000 election, the 2003 election, and the 2006 election), so this was the second mayoral election since the city's 2005 change to instant-runoff voting (IRV).4. How did this change to IRV come about?
''Over 64% of Burlington voters voted in favor of the IRV Charter amendment in March 2005, and it went into effect on May 12, 2005, when the governor signed the ratification bill, H.505, which had been passed by both the House and Senate.''
In the 2009 election, incumbent
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Instant Run-off Voting
Instant-runoff voting (IRV) is a type of ranked preferential voting method. It uses a majority voting rule in single-winner elections where there are more than two candidates. It is commonly referred to as ranked-choice voting (RCV) in the United States (although there are other forms of ranked voting), preferential voting in Australia, where it has seen the widest adoption; in the United Kingdom, it is generally called alternative vote (AV), whereas in some other countries it is referred to as the single transferable vote, which usually means only its multi-winner variant. All these names are often used inconsistently. Voters in IRV elections rank the candidates in order of preference. Ballots are initially counted for each voter's top choice. If a candidate has more than half of the first-choice votes, that candidate wins. If not, then the candidate with the fewest votes is eliminated, and the voters who selected the defeated candidate as a first choice then have their vote ...
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Instant Run-off Voting
Instant-runoff voting (IRV) is a type of ranked preferential voting method. It uses a majority voting rule in single-winner elections where there are more than two candidates. It is commonly referred to as ranked-choice voting (RCV) in the United States (although there are other forms of ranked voting), preferential voting in Australia, where it has seen the widest adoption; in the United Kingdom, it is generally called alternative vote (AV), whereas in some other countries it is referred to as the single transferable vote, which usually means only its multi-winner variant. All these names are often used inconsistently. Voters in IRV elections rank the candidates in order of preference. Ballots are initially counted for each voter's top choice. If a candidate has more than half of the first-choice votes, that candidate wins. If not, then the candidate with the fewest votes is eliminated, and the voters who selected the defeated candidate as a first choice then have their vote ...
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Smith Set
In voting systems, the Smith set, named after John H. Smith, but also known as the top cycle, or as Generalized Top-Choice Assumption (GETCHA), is the smallest non-empty set of candidates in a particular election such that each member defeats every candidate outside the set in a pairwise election. The Smith set provides one standard of optimal choice for an election outcome. Voting systems that always elect a candidate from the Smith set pass the Smith criterion and are said to be 'Smith-efficient' or to satisfy the Smith criterion. A set of candidates each of whose members pairwise defeats every candidate outside the set is known as a dominating set. The Smith set can be seen as defining a voting method (Smith's method) which is most often encountered when extended by an IRV tie-break as Smith/IRV or as Tideman's Alternative, or by minimax as Smith/minimax. Properties of Smith sets *The Smith set always exists and is well defined (see next section). *The Smith set can have mo ...
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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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Instant Runoff Voting
Instant-runoff voting (IRV) is a type of ranked preferential voting method. It uses a majority voting rule in single-winner elections where there are more than two candidates. It is commonly referred to as ranked-choice voting (RCV) in the United States (although there are other forms of ranked voting), preferential voting in Australia, where it has seen the widest adoption; in the United Kingdom, it is generally called alternative vote (AV), whereas in some other countries it is referred to as the single transferable vote, which usually means only its multi-winner variant. All these names are often used inconsistently. Voters in IRV elections rank the candidates in order of preference. Ballots are initially counted for each voter's top choice. If a candidate has more than half of the first-choice votes, that candidate wins. If not, then the candidate with the fewest votes is eliminated, and the voters who selected the defeated candidate as a first choice then have their vote ...
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Nicolaus Tideman
Thorwald Nicolaus Tideman (, not ; born August 11, 1943 in Chicago, Illinois) is a Georgist economist and professor at Virginia Tech. He received his Bachelor of Arts in economics and mathematics from Reed College in 1965 and his PhD in economics from the University of Chicago in 1969. Tideman was an Assistant Professor of Economics at Harvard University from 1969-1973, during which time from 1970-1971 he was a Senior Staff Economist for the President's Council of Economic Advisors. Since 1973, he has been at Virginia Tech, with various visiting positions at Harvard Kennedy School (1979-1980), University of Buckingham (1985-1986), and the American Institute for Economic Research (1999-2000). Research Tideman's academic interests include taxation of land, voting theory, and political philosophy. Ranked Pairs In 1987, he devised the voting system called "ranked pairs" (or the "Tideman method" or simply "RP"), which is a type of Condorcet method. It selects a single winner us ...
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