Plurality voting refers to electoral systems in which the candidates in an electoral district who poll more than any other are elected.
The two-round system, also called ballotage, top-two runoff, or two-round plurality, is a single winner voting method. It is sometimes called plurality-runoff, although this term can also be used for other, closely-related systems such as ranked-choice voting or the exhaustive ballot. It falls under the class of plurality-based voting rules, together with instant-runoff and first-past-the-post (FPP). In a two-round system, both rounds are held under choose-one voting, where the voter marks a single favorite candidate. The two candidates with the most votes in the first round proceed to a second round, where all other candidates are excluded.
In political science, Duverger's law holds that in political systems with single-member districts and the plurality voting system,, two main parties tend to emerge. In this case, votes for minor parties can potentially be regarded splitting votes away from the most similar major party. In contrast, systems with proportional representation usually have more representation of minor parties in government.
A Condorcet method is an election method that elects the candidate who wins a majority of the vote in every head-to-head election against each of the other candidates, whenever there is such a candidate. A candidate with this property, the pairwise champion or beats-all winner, is formally called the Condorcet winner or Pairwise Majority Rule Winner (PMRW). The head-to-head elections need not be done separately; a voter's choice within any given pair can be determined from the ranking.
Voting refers to the process of choosing officials or policies by casting a ballot, a document used by people to formally express their preferences. Republics and representative democracies are governments where the population chooses representatives by voting.
Coombs' method is a ranked voting system. Like instant-runoff (IRV-RCV), Coombs' method is a sequential-loser method, where the last-place finisher according to one method is eliminated in each round. However, unlike in instant-runoff, each round has electors voting against their least-favorite candidate; the candidate ranked last by the most voters is eliminated.
Third party, or minor party, is a term used in the United States' two-party system for political parties other than the Republican and Democratic parties.
In social choice theory, the majority rule (MR) is a social choice rule which says that, when comparing two options, the option preferred by more than half of the voters should win.
An electoraldistrict, sometimes called a constituency, riding, or ward, is a subdivision of a larger state created to provide its population with representation in the larger state's legislature. That body, or the state's constitution or a body established for that purpose, determines each district's boundaries and whether each will be represented by a single member or multiple members. Generally, only voters (constituents) who reside within the district are permitted to vote in an election held there. District representatives may be elected by a first-past-the-post system, a proportional representative system, or another voting method. They may be selected by a direct election under universal suffrage, an indirect election, or another form of suffrage.
Positional voting is a ranked voting electoral system in which the options or candidates receive points based on their rank position on each ballot and the one with the most points overall wins. The lower-ranked preference in any adjacent pair is generally of less value than the higher-ranked one. Although it may sometimes be weighted the same, it is never worth more. A valid progression of points or weightings may be chosen at will or it may form a mathematical sequence such as an arithmetic progression, a geometric one or a harmonic one. The set of weightings employed in an election heavily influences the rank ordering of the candidates. The steeper the initial decline in preference values with descending rank, the more polarised and less consensual the positional voting system becomes.
In social choice theory, the best-is-worst paradox occurs when a voting rule declares the same candidate to be both the best and worst possible winner. The worst candidate can be identified by reversing each voter's ballot, then applying the voting rule to the reversed ballots find a new "anti-winner".
Woodall'splurality criterion is a voting criterion for ranked voting. It is stated as follows:
Later-no-harm is a property of some 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.
An electoral list is a grouping of candidates for election, usually found in proportional or mixed electoral systems, but also in some plurality electoral systems. An electoral list can be registered by a political party or can constitute a group of independent candidates. Lists can be open, in which case electors have some influence over the ranking of the winning candidates, or closed, in which case the order of candidates is fixed at the registration of the list.
Plurality block voting, a type of block voting method for multi-winner elections. Each voter may cast as many votes as the number of seats to be filled. The candidates with the most votes are elected. The usual result when the candidates divide into parties is that the most-popular party in the district sees its full slate of candidates elected, even if the party does not not have support of majority of the voters.
The Borda method or order of merit is a positional voting rule which gives each candidate a number of points equal to the number of candidates ranked below them: the lowest-ranked candidate gets 0 points, the second-lowest gets 1 point, and so on. Once all votes have been counted, the option or candidate with the most points is the winner.
Instant-runoff voting (IRV) is a winner-takes-all multi-round elimination voting system that uses ranked voting to simulate a series of runoff elections, where the last-place finisher according to a plurality vote is eliminated in each round and the votes supporting the eliminated choice are transferred to their next available preference until one of the options reaches a majority of the remaining votes. Its purpose is to elect the candidate in single-member districts with majority support even when there are more than two candidates. IRV is most closely related to two-round runoff election.
The 2009 Burlington mayoral election was the second mayoral election since the city's 2005 change to instant-runoff voting (IRV), also known as ranked-choice voting (RCV), after the 2006 mayoral election. In the 2009 election, incumbent Burlington mayor won reelection as a member of the Vermont Progressive Party, defeating Kurt Wright in the final round with 48% of the vote.
An electoral or voting system is a set of rules used to determine the results of an election. 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.
Ranked voting is any voting system that uses voters' rankings of candidates to choose a single winner or multiple winners. More formally, a ranked system is one that depends only on which of two candidates is preferred by a voter, and as such does not incorporate any information about intensity of preferences. Ranked voting systems vary dramatically in how preferences are tabulated and counted, which gives them very different properties.
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