ALTERNATIVE VOTE (AV): An alternative name for "Single-Winner Ranked Choice Voting".
APPROVAL VOTING: A voting system used in single-winner district systems and single-office elections in which voters can vote for, or approve of, as many candidates as they wish. Each candidate approved receives one vote and the candidate with the most votes wins. The winner need not garner a majority of the votes.
AT-LARGE: A type of electoral jurisdiction where representatives are elected from the whole political region (i.e.: a city, county, state or nation).
BALLOT IMAGE DATA: Records of the contents of each individual vote cast by each and every voter in a jurisdiction (with all identifying information removed).
BALLOT STRUCTURE: The way in which electoral choices are presented on the ballot paper.
BLOCK VOTE: A winner-take-all voting system used in multi-winner districts where electors have as many votes as there are candidates to be elected. Voting can be either candidate-centered or party-centered. Counting is identical to a plurality system, with the candidates with the highest vote totals winning the seats. Also known as the Bloc Vote.
BORDA COUNT: A non-proportional form of preferential voting where voters rank candidates. These ranking are converted into points; the candidate with the most points wins. Candidates score one point for being ranked last, two for being next-to-last and so on, with the first-choice candidate receiving points equal to the total number of candidates. For example, in an election with five candidates, a first ranked candidate would receive five points, a second ranked office seeker four and so on.
BULLET VOTING: A vote in which the voter has selected only one candidate, despite the option to indicate a preference for more than one candidates. Voters may bullet vote strategically (in block voting systems), in a misguided attempt to vote strategically (in the case of ranked choice voting) or because the voter lacks the information or will to evaluate more than one candidate on the ballot.
CANDIDATE-CENTERED BALLOT: A form of balloting where an elector chooses between candidates.
CHOICE VOTING: Another term for "Multi-winner Ranked Choice Voting".
CLOSED LIST: A form of list proportional representation in which electors are restricted to voting for a party only, and cannot express a preference for any candidate within a party list.
COMPENSATORY SEATS: The party list seats in a mixed-member proportional (MMP) system awarded to parties based on their proportion of the national vote. These seats are designed to correct the often disproportionate results of plurality-majority elections.
CONTIGUOUS DISTRICTS: Districts comprised of areas geographically adjoined or touching.
CUMULATIVE VOTE: A semi-proportional system, used in some American localities, that uses multi-winner districts. Voters have the same number of votes as seats and may allocate them among the candidates in any way they see fit including giving more than one vote to a particular candidate.
DESCRIPTIVE REPRESENTATION: The idea that a body of elected representatives should reflect the outward characteristics, such as such as occupation, race, ethnicity, or gender, of the populations they represent.
DISTRIBUTION REQUIREMENTS: The requirement that a winning candidate must not merely win a specified proportion of the vote nationally but also a specified degree of support from different regions.
DISTRICT: The geographical regions into which a city, state, or country is divided for election purposes. Single-winner districts elect one member of the legislature whereas multi-winner districts elect two or more.
DISTRICT MAGNITUDE: The number of candidates to be elected in each district.
DROOP QUOTA: Used in highest average method and multi-winner ranked choice voting elections to determine the number of votes necessary to win a seat. The threshold is intended to be the lowest vote total that only the winning number of candidates can get. The quota is ascertained by the following formula: total vote divided by the number of seats plus one, then one is added to the product.
ELECTORAL FORMULA: That part of the electoral system dealing specifically with the translation of votes into seats.
ELECTORAL LAW: The constitutional and legal provisions governing all aspects of the electoral process.
ELECTORAL SYSTEM: A set of rules and procedures that govern the election of public officials by specifying, chiefly, the electoral formula, the ballot structure, and district magnitude.
FIRST PAST THE POST (FPTP): Another name for "Plurality".
FREE LIST: A form of list system PR providing for cumulative voting.
FULL REPRESENTATION: A term used by proportional representation proponents to describe electoral systems that aim to reduce the disparity between a party's share of the national vote in a legislative election and its share of seats. For example, if a party wins 40% of the votes, it should win approximately 40% of the seats.
GENDER PARITY: The political condition under which women and men are just as likely to hold elected office.
GERRYMANDERING: The manipulation of district boundary lines in order to advantage or disadvantage a candidate or political group. Gerrymandering is typically used to create a district that is favorable to an incumbent, advantage a particular party or political group to receive more seats than its proportion of the vote, or to conversely disenfranchise a group or party by weakening or dividing that subset of the electorate.
HAGENBACH-BISCHOFF FORMULA: Another term for the Droop Quota.
HARE QUOTA: Used in largest remainder full representation systems to determine how many votes are needed to win a seat. The quota is ascertained by dividing the total vote by the number of seats.
HIGHEST AVERAGE METHOD: A family of formulas used with list systems to translate votes into seats, including the d'Hondt formula and the Sainte-Lague Formula. Party vote totals are divided by a series of divisors, which differ according to the system used. After each stage, the party with the highest average wins the seat.
IMPERIALI QUOTA: Sometimes used in largest remainder systems to determine how many votes are necessary to win a seat. The quota is ascertained by dividing the total vote by the number of seats plus two.
INDEX OF DISPROPORTIONALITY: A figure illustrating the collective disparity between the votes cast for parties in an election and the seats in a legislature they win.
INSTANT RUNOFF VOTING (IRV): Another term for "Single-winner Ranked Choice Voting".
INVALID VOTES: Ballots cast that are unable to be included in the vote total due to accidental or deliberate errors on the ballot.
LARGEST REMAINDER METHOD: General term for the Hare Quota, and the Droop and Imperiali calculation methods, which translate votes into seats within List PR systems. There are two stages to the count. First, parties are awarded seats in proportion to the number of quotas they fulfill (quotas vary depending on which of the three systems are used). Second, remaining seats are awarded to parties on the basis of the leftover votes they possess after the 'quota' stage of the count. Largest remainder seats are allocated in order of vote size.
LIMITED VOTE: A voting system used in multi-winner districts; electors have more than one vote but fewer votes than there are candidates to be elected. Counting is identical to a plurality system, with the candidates with the highest vote totals winning the seats. When voters have only one vote, it is also known as the Single Vote system or the single non-transferable vote (SNTV).
LIST PROPORTIONAL REPRESENTATION: A form of proportional representation used in multi-winner elections where the party submits lists of candidates to be elected. Voters vote for the party. The seats are allocated to each party in proportion to the share received in the national vote. Party lists of candidates can be open, closed, or free. List proportional representation are also known as party list proportional or list systems or List PR.
MAJORITY-RUNOFF: Another name for the "Two Round System".
MALAPPORTIONMENT: The uneven distribution of voters between electoral districts.
MIXED MEMBER PROPORTIONAL (MMP): A hybrid electoral system where some legislative seats are elected from single-winner districts suing winner-take-all rules (i.e. plurality) and the remainder from party list proportional systems. MMP combines geographic representation with proportional representation of ideological interests. Party list seats are allocated in such a way as to achieve proportionality in the legislative chamber overall.
MONOTONICITY: The characteristic of a voting system in which it is neither possible to prevent the election of a candidate by ranking them higher on some of the ballots, nor possible to elect an otherwise unelected candidate by ranking them lower on some of the ballots (while nothing else is altered on any ballot).
MULTI-WINNER DISTRICT: A district from which more than one member is elected.
MULTI-WINNER PLURALITY VOTING SYSTEM: Another name for "Block Voting".
MULTI-WINNER RANKED CHOICE VOTING: A proportional voting system used in at-large or multi-winner district elections where voters rank candidates in order of preference. Candidates win by reaching a threshold through a process of surplus transfers and eliminations.
NUMBERED POSTS: An electoral system in which candidates run for a particular post but are elected at-large. Some numbered posts require that the candidate be a resident of a particular geographical area.
ONE VOTE SYSTEM: Another term for the "Single Vote".
OPEN LIST: A form of List PR in which electors can express a preference for the order of candidates within a party list, as well as voting for the party.
OVERVOTE: A vote in which the voter has indicated a preference for more than the maximum number of selections allowed.
PARALLEL SYSTEM: A hybrid electoral system where some legislatives seats are elected from single-winner districts suing winner-take-all rules (i.e. plurality) and the remainder from party list proportional systems. Unlike MMP, proportionality is confined to the party lists seats, rather than applying to the legislative chamber overall.
PARTY-CENTERED BALLOT: A form of ballot in which an elector chooses between parties.
PLURALITY: A voting system used in single-winner elections in which the candidate with the most votes wins, without necessarily receiving a majority of votes. It is the most common system used in countries descended from the British and French Empires, including the United States and Canada. Certain jurisdictions couple the use of plurality with runoff elections if no winner attains the majority of votes in the initial election (this is called the "Two Round System").
POLARIZATION: In voting rights, polarization describes a division where voters cast their votes along racial lines. For example, an area would exhibit polarized voting if most white voters support a particular candidate and most black voters support another candidate.
PREFERENTIAL VOTING: Electoral systems in which voters can rank-order candidates on the ballot paper in order of their choice. Ranked choice voting, Borda count, Bucklin Voting, and Coomb's method are all examples of preferential voting. In other contexts, preferential voting may be a synoym for single-winner ranked choice voting (in Australia) or open list proportional representation (in some parts of Europe).
PROPORTIONAL REPRESENTATION: A group of voting systems used in many democracies whose major goal is to ensure that parties and political groups are allocated seats in legislative bodies in proportion to their share of the vote. For example, a party receiving 30% of the national vote should receive approximately 30% of the seats in the national legislature.
RANKED CHOICE VOTING: Two voting systems in which voters express their preferences for candidates by ranking them. Ranked choice voting may be single- or multi-winner. See also "Multi-winner Ranked Choice Voting" and "Single-winner Ranked Choice Voting"
REFLECTIVE REPRESENTATION: Another term for "descriptive representation".
RESERVED SEATS: Seats in which some ascriptive criterion such as religion, ethnicity, language, gender etc. is a requirement for election.
RESIDUAL VOTES: Total number of votes that cannot be counted for a specific contest. There are multiple types of residual votes, including overvotes and undervotes.
RUNOFF ELECTIONS: An election method where the top two candidates face off in a second round of voting if no candidate wins a majority (or lower, pre-determined vote) in the first round.
SAINTE-LAGUE FORMULA: A highest-average formula for allocating seats proportionally in a list system. The available seats are awarded one at a time to the party with the largest average number of votes as determined by dividing the number of votes won by the party by the number of seats the party has been awarded plus one. Each time a party wins a seat, the divisor for that party increases by two, which thus reduces its chances of winning the next seat. The first seat is awarded to the party with the largest absolute number of votes, since, no seats having been allocated, the average vote total as determined by the formula will be largest for this party (see also d'Hondt formula).
SEMI-PROPORTIONAL SYSTEMS: Those electoral systems where proportional outcomes (groups winning seats according to their population percentage) in elections may be produced, but are not guaranteed. Semi-proportional systems generally produces electoral results that are between the proportionality of full representation systems and the disproportionality of winner-take-all systems. These systems include cumulative voting and limited voting.
SINCERE VOTING: A term used to describe votes cast by voters for their most preferred candidate. This contrasts with "insincere" or "strategic" voting where voters must cast a vote for a candidate other than their first preference in order to best pursue their political interests.
SINGLE NON-TRANSFERABLE VOTE (SNTV): Another term for "Single Vote".
SINGLE VOTE: A multi-winner system in which electors have one vote. The candidates with the most votes win.
SINGLE-WINNER DISTRICT: A district from which only one member is elected.
SINGLE-WINNER RANKED CHOICE VOTING: An electoral system used in single-winner elections where voters rank candidates in order of preference. If a candidate has more than half of the vote based on first-choices, that candidate wins. If no candidate has more than half of those votes, then the candidate with the fewest first choices is eliminated. The voters who selected the defeated candidate as a first choice will then have their votes added to the totals of their next choice. This process continues until a candidate has more than half of the active votes or only two candidates remain. The candidate with a majority among the active candidates is declared the winner.
SPOILER EFFECT: A phenomenon in plurality elections in which an independent or third party candidate takes enough votes away from one major party candidate to ensure the victory of the other major party candidate, who would not have won otherwise.
STRATEGIC (OR TACTICAL) VOTING: Occurs when a voter votes for a candidate other than her sincere choice to prevent an unwanted outcome. For example, in a plurality election, there is often a strong incentive for supporters of a minor party to throw their vote to a larger party with a greater chance of victory; this prevents a party or candidate the voter dislikes from winning. Generally speaking, proportional voting systems are designed to reduce strategic voting, as the results will closely match the total share of votes cast for each party.
THRESHOLD: The minimum numbers of the votes needed to receive any seats in the legislature under a proportional representation system. Known technically as the threshold of exclusion in List PR, because if a party reaches this threshold they cannot be excluded from winning a seat. Under choice voting, the threshold is the fewest number of votes that only the winning number of candidates can obtain (roughly the number of votes divided by the number of seats.
TWO-ROUND SYSTEM: A winner-take-all system in which a second election is held if no candidate achieves an absolute majority of votes in the first election. Also known as "runoff elections".
TWO-TIER DISTRICTING: Where seats are awarded to parties from both single member districts and national lists, or both regional and national lists.
UNDERVOTE: A vote in which the voter has selected fewer candidates than allowed or has skipped voting for the office entirely.
WASTED VOTES: A political science term used to describe votes that are not useful in the election of the winning candidate or party. Those votes include ballots cast for a losing candidate(s) along with any extraneous votes cast in support of winning candidates.
WINNER-TAKE-ALL: A term used to describe election systems that award seats to the highest vote getters without ensuring fair representation for minority groups. In the United States, these are typically single-winner district schemes or at-large, block-voting systems.