Majority criterionThe majority criterion is a single-winner voting system criterion, used to compare such systems. The criterion states that "if one candidate is ranked first by a majority (more than 50%) of voters, then that candidate must win". Some methods that comply with this criterion include any Condorcet method, instant-runoff voting, Bucklin voting, and plurality voting.
Electoral thresholdThe electoral threshold, or election threshold, is the minimum share of all the votes cast that a candidate or political party requires to achieve before they become entitled to representation or additional seats in a legislature. This limit can operate in various ways, e.g. in party-list proportional representation systems where an electoral threshold requires that a party must receive a specified minimum percentage of votes (e.g. 5%), either nationally or in a particular electoral district, to obtain seats in the legislature.
Mixed-member proportional representationMixed-member proportional representation (MMP or MMPR) is a mixed electoral system in which votes are cast for both local elections and also for overall party vote tallies, which are used to allocate additional members to produce or deepen overall proportional representation. In some MMP systems, voters get two votes: one to decide the representative for their single-seat constituency, and one for a political party. In Denmark and others, the single vote cast by the voter is used for both the local election (in a multi-member or single-seat district), and for the overall top-up.
United States House of RepresentativesThe United States House of Representatives is the lower chamber of the United States Congress, with the Senate being the upper chamber. Together, they comprise the national bicameral legislature of the United States. The House's composition was established by Article One of the United States Constitution. The House is composed of representatives who, pursuant to the Uniform Congressional District Act, sit in single member congressional districts allocated to each state on the basis of population as measured by the United States census, with each district having one representative, provided that each state is entitled to at least one.
Duverger's lawIn political science, Duverger's law holds that single-ballot majoritarian elections with single-member districts (such as first past the post) tend to favor a two-party system. The theory is attributed to Maurice Duverger, a French sociologist who published several papers on it in the 1950s and 1960s. In the course of further research, other political scientists began calling the effect a "law" or principle. As a corollary to the law, Duverger also asserted that proportional representation favors multi-partyism, as does the plurality system with runoff elections.
Secret ballotThe secret ballot, also known as the Australian ballot, is a voting method in which a voter's identity in an election or a referendum is anonymous. This forestalls attempts to influence the voter by intimidation, blackmailing, and potential vote buying. This system is one means of achieving the goal of political privacy. Secret ballots are used in conjunction with various voting systems. The most basic form of a secret ballot utilizes blank pieces of paper upon which each voter writes their choice.
Postal votingPostal voting is voting in an election where ballot papers are distributed to electors (and typically returned) by post, in contrast to electors voting in person at a polling station or electronically via an electronic voting system. In an election, postal votes may be available on demand or limited to individuals meeting certain criteria, such as a proven inability to travel to a designated polling place. Most electors are required to apply for a postal vote, although some may receive one by default.
Arrow's impossibility theoremArrow's impossibility theorem, the general possibility theorem or Arrow's paradox is an impossibility theorem in social choice theory that states that when voters have three or more distinct alternatives (options), no ranked voting electoral system can convert the ranked preferences of individuals into a community-wide (complete and transitive) ranking while also meeting the specified set of criteria: unrestricted domain, non-dictatorship, Pareto efficiency, and independence of irrelevant alternatives.
Party-list proportional representationParty-list proportional representation (list-PR) is a subset of proportional representation electoral systems in which multiple candidates are elected (e.g., elections to parliament) through their position on an electoral list. They can also be used as part of mixed-member electoral systems. In these systems, parties make lists of candidates to be elected, and seats are distributed by elections authorities to each party in proportion to the number of votes the party receives.
Single non-transferable voteSingle non-transferable vote or SNTV is an electoral system used to elect multiple winners. It is a generalization of first-past-the-post, applied to multi-member districts with each voter casting just one vote. Unlike FPTP, which is a single-winner system, in SNTV multiple winners are elected, typically in electoral districts; additionally, unlike FPTP, SNTV produces mixed representation and makes it unlikely for a single party to take all the seats in a city or a set area, which can happen under FPTP.
