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Participation Criterion
The participation criterion is a voting system criterion. Voting systems that fail the participation criterion are said to exhibit the no show paradox and allow a particularly unusual strategy of tactical voting: abstaining from an election can help a voter's preferred choice win. The criterion has been defined as follows: * In a deterministic framework, the participation criterion says that the addition of a ballot, where candidate A is strictly preferred to candidate B, to an existing tally of votes should not change the winner from candidate A to candidate B. * In a probabilistic framework, the participation criterion says that the addition of a ballot, where each candidate of the set X is strictly preferred to each other candidate, to an existing tally of votes should not reduce the probability that the winner is chosen from the set X. Plurality voting, approval voting, range voting, and the Borda count all satisfy the participation criterion. All Condorcet methods, Bucklin vo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Comparison Of Electoral Systems
Electoral systems are the rules for conducting elections, a main component of which is the algorithm for determining the winner (or several winners) from the ballots cast. This article discusses methods and results of comparing different electoral systems, both those which elect a unique candidate in a 'single-winner' election and those which elect a group of representatives in a multiwinner election. There are 4 main types of reasoning which have been used to try to determine the best voting method: # Argument by example # Adherence to logical criteria # Results of simulated elections # Results of real elections Expert opinions on single-winner voting methods In 2010, a panel of 22 experts on voting procedures were asked: "What is the best voting rule for your town to use to elect the mayor?". One member abstained. Approval voting was used to decide between 18 single-winner voting methods. The ranking (with number ''N'' of approvers from a maximum of 21) of the various syst ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mechanism Design
Mechanism design is a field in economics and game theory that takes an objectives-first approach to designing economic mechanisms or incentives, toward desired objectives, in strategic settings, where players act rationally. Because it starts at the end of the game, then goes backwards, it is also called reverse game theory. It has broad applications, from economics and politics in such fields as market design, auction theory and social choice theory to networked-systems (internet interdomain routing, sponsored search auctions). Mechanism design studies solution concepts for a class of private-information games. Leonid Hurwicz explains that 'in a design problem, the goal function is the main "given", while the mechanism is the unknown. Therefore, the design problem is the "inverse" of traditional economic theory, which is typically devoted to the analysis of the performance of a given mechanism.' So, two distinguishing features of these games are: * that a game "designer" ch ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Douglas Woodall
Douglas Robert Woodall (born November 1943 in Stoke-on-Trent) is a British mathematician and psephologist. He studied mathematics at the University of Cambridge, and earned his Ph.D. at the University of Nottingham in 1969, his thesis being "Some results in combinatorial mathematics". He worked in the Department of Mathematics from 1969 until his retirement in 2007, as researcher, lecturer, associate professor and reader. He devised the later-no-harm criterion, a voting system criterion that is considered important in the comparison of electoral systems. Woodall has done a lot of work exploring the monotonicity criterion. He also contributed to the problem of fair cake-cutting, for example, by presenting an algorithm for finding a super-proportional division. Selected publications * * * * * See also *Woodall's conjecture on dicuts and dijoin In mathematics, a dijoin is a subset of the edges of a directed graph, with the property that contracting every edge ... [...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 m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Consistency Criterion
A voting system is consistent if, whenever the electorate is divided (arbitrarily) into several parts and elections in those parts garner the same result, then an election of the entire electorate also garners that result. Smith calls this property separability and Woodall calls it convexity. It has been proven a ranked voting system is "consistent if and only if it is a scoring function", i.e. a positional voting system. Borda count is an example of this. The failure of the consistency criterion can be seen as an example of Simpson's paradox. As shown below under Kemeny-Young, passing or failing the consistency criterion can depend on whether the election selects a single winner or a full ranking of the candidates (sometimes referred to as ranking consistency); in fact, the specific examples below rely on finding single winner inconsistency by choosing two different rankings with the same overall winner, which means they do not apply to ranking consistency. Examples C ... [...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 \operatorn ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hervé Moulin
Hervé Moulin (born 1950 in Paris) is a French mathematician who is the Donald J. Robertson Chair of Economics at the Adam Smith Business School at the University of Glasgow. He is known for his research contributions in mathematical economics, in particular in the fields of mechanism design, social choice, game theory and fair division. He has written five books and over 100 peer-reviewed articles. Moulin was the George A. Peterkin Professor of Economics at Rice University (from 1999 to 2013):, the James B. Duke Professor of Economics at Duke University (from 1989 to 1999) and the University Distinguished Professor at Virginia Tech (from 1987 to 1989). He is a fellow of the Econometric Society since 1983, and the president of the Game Theory Society for the term 2016 - 2018. He also served as president of the Society for Social Choice and Welfare for the period of 1998 to 1999. He became a Fellow of the Royal Society of Edinburgh in 2015. Moulin's research has been s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Referendum
A referendum (plural: referendums or less commonly referenda) is a direct vote by the electorate on a proposal, law, or political issue. This is in contrast to an issue being voted on by a representative. This may result in the adoption of a new policy or specific law, or the referendum may be only advisory. In some countries, it is synonymous with or commonly known by other names including plebiscite, votation, popular consultation, ballot question, ballot measure, or proposition. Some definitions of 'plebiscite' suggest it is a type of vote to change the constitution or government of a country. The word, 'referendum' is often a catchall, used for both legislative referrals and initiatives. Etymology 'Referendum' is the gerundive form of the Latin verb , literally "to carry back" (from the verb , "to bear, bring, carry" plus the inseparable prefix , here meaning "back"Marchant & Charles, Cassell's Latin Dictionary, 1928, p. 469.). As a gerundive is an adjective,A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quorum
A quorum is the minimum number of members of a deliberative assembly (a body that uses parliamentary procedure, such as a legislature) necessary to conduct the business of that group. According to '' Robert's Rules of Order Newly Revised'', the "requirement for a quorum is protection against totally unrepresentative action in the name of the body by an unduly small number of persons." In contrast, a plenum is a meeting of the full (or rarely nearly full) body. A body, or a meeting or vote of it, is quorate if a quorum is present (or casts valid votes). The term ''quorum'' is from a Middle English wording of the commission formerly issued to justices of the peace, derived from Latin ''quorum'', "of whom", genitive plural of ''qui'', " who". As a result, ''quora'' as plural of ''quorum'' is not a valid Latin formation. In modern times a quorum might be defined as the minimum number of voters needed for a valid election. In ''Robert's Rules of Order'' According to Robert, eac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Social Choice
Social choice theory or social choice is a theoretical framework for analysis of combining individual opinions, preferences, interests, or welfares to reach a ''collective decision'' or ''social welfare'' in some sense.Amartya Sen (2008). "Social Choice,". ''The New Palgrave Dictionary of Economics'', 2nd EditionAbstract & TOC./ref> Whereas choice theory is concerned with individuals making choices based on their preferences, social choice theory is concerned with how to translate the preferences of individuals into the preferences of a group. A non-theoretical example of a collective decision is enacting a law or set of laws under a constitution. Another example is voting, where individual preferences over candidates are collected to elect a person that best represents the group's preferences. Social choice blends elements of welfare economics and public choice theory. It is methodologically individualistic, in that it aggregates preferences and behaviors of individual memb ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tactical Voting
Strategic voting, also called tactical voting, sophisticated voting or insincere voting, occurs in voting systems when a voter votes for another candidate or party than their ''sincere preference'' to prevent an undesirable outcome. For example, in a simple plurality election, a voter might gain a better outcome by voting for a less preferred but more generally popular candidate. Gibbard's theorem shows that ''all'' single-winner voting methods are susceptible to strategic voting, unless there are only two options or ''dictatorial'' (i.e., a distinguished agent exists who can impose the outcome). For multi-winner elections no general theorem for strategic voting exists. Strategic voting is observed due to non-proportionality, electoral thresholds and quotas. Types of strategic voting ; (sometimes "useful vote"): A voter insincerely ranks an alternative higher in the hope of getting that candidate elected. For example, in the first-past-the-post election, voters may vote fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
