| Part of the Politics and Economics series |
| Electoral systems |
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 Politicsportal  Economicsportal |
In proportional representation systems, an electoral quota is the number of votes a candidate needs to be guaranteed election.
| Part of the Politics and Economics series |
| Electoral systems |
|---|
| |
| Politicsportal Economicsportal |
In proportional representation systems, an electoral quota is the number of votes a candidate needs to be guaranteed election.
An admissible quota is a quota that is guaranteed to apportion only as many seats as are available in the legislature. Such a quota can be any number between: [1]
There are two commonly-used quotas: the Hare and Droop quotas. The Hare quota is unbiased in the number of seats it hands out, and so is more proportional than the Droop quota (which tends to be biased towards larger parties); [2] [3] however, the Droop quota guarantees that a party that wins a majority of votes in a district will win a majority of the seats in the district. [4] [5]
The Hare quota (also known as the simple quota or Hamilton's quota) is the most commonly-used quota for apportionments using the largest remainder method of party-list representation. It was used by Thomas Hare in his first proposals for STV. It is given by the expression:
Specifically, the Hare quota is unique in being unbiased in the number of seats it hands out. This makes it more proportional than the Droop quota (which is biased towards larger parties). [2]
The Hare quota gives no advantage to larger or smaller parties. [6] However, in small legislatures with no threshold, the Hare quota can be manipulated by running candidates on many small lists, allowing each list to pick up a single remainder seat. [7]
The Droop quota is used in most single transferable vote (STV) elections today and is occasionally used in elections held under the largest remainder method of party-list proportional representation (list PR). It is given by the expression: [1] [8]
It was first proposed in 1868 by the English lawyer and mathematician Henry Richmond Droop (1831–1884), who identified it as the minimum amount of support needed to secure a seat in semiproportional voting systems such as SNTV, leading him to propose it as an alternative to the Hare quota. [9]
However, the Droop quota has a substantial seat bias in favor of larger parties; [6] in fact, the Droop quota is the most-biased possible quota that can still be considered to be proportional. [1]
Today the Droop quota is used in almost all STV elections, including those in India, the Republic of Ireland, Northern Ireland, Malta, and Australia.[ citation needed ]
Party-list proportional representation (list-PR) is a system of proportional representation based on preregistered political parties, with each party being allocated a certain number of seats roughly proportional to their share of the vote.
The single transferable vote (STV), a type of proportional ranked choice voting (P-RCV), is a multi-winner electoral system in which each voter casts a single vote in the form of a ranked-choice ballot. Voters have the option to rank candidates, and their vote may be transferred according to alternative preferences if their preferred candidate is eliminated or elected with surplus votes, so that their vote is used to elect someone they prefer over others in the running. STV aims to approach proportional representation based on votes cast in the district where it is used, so that each vote is worth about the same as another.
In the study of electoral systems, the Droop quota is the minimum number of votes needed for a party or candidate to guarantee they will win at least one seat in a legislature.
The D'Hondt method, also called the Jefferson method or the greatest divisors method, is an apportionment method for allocating seats in parliaments among federal states, or in proportional representation among political parties. It belongs to the class of highest-averages methods. Compared to ideal proportional representation, the D'Hondt method reduces somewhat the political fragmentation for smaller electoral district sizes, where it favors larger political parties over small parties.
The Webster method, also called the Sainte-Laguë method, is a highest averages apportionment method for allocating seats in a parliament among federal states, or among parties in a party-list proportional representation system. The Sainte-Laguë method shows a more equal seats-to-votes ratio for different sized parties among apportionment methods.
The highest averages, divisor, or divide-and-round methods are a family of apportionment algorithms that aim to fairly divide a legislature between several groups, such as political parties or states. More generally, divisor methods can be used to round shares of a total, e.g. percentage points.
The largest remainder methods or quota methods are methods of allocating seats proportionally that are based on calculating a quota, i.e. a certain number of votes needed to be guaranteed a seat in parliament. Then, any leftover seats are handed over to "plurality" winners. They are typically contrasted with the more popular highest averages methods.
The Imperiali quota or pseudoquota is an inadmissible electoral quota named after Belgian senator Pierre Imperiali. Some election laws have mandated it as the number of votes needed to earn a seat in single transferable vote or largest remainder elections.
In the study of apportionment, the Harequota is the number of voters represented by each legislator under an idealized system of proportional representation, where every legislator represents an equal number of voters. The Hare quota is the total number of votes divided by the number of seats to be filled. The Hare quota was used in the original proposal for a single transferable vote system, and is still occasionally used, although it has since been largely supplanted by the Droop quota.
The single transferable vote (STV) is a semi-proportional representation system that elects multiple winners. It is one of several ways of choosing winners from ballots that rank candidates by preference. Under STV, an elector's vote is initially allocated to their first-ranked candidate. Candidates are elected (winners) if their vote tally reaches quota. After the winners in the first count are determined, if seats are still open, surplus votes — those in excess of an electoral quota— are transferred from winners to the remaining candidates (hopefuls) according to the surplus ballots' next usable back-up preference.
The Huntington–Hill method is a highest averages method for assigning seats in a legislature to political parties or states. Since 1941, this method has been used to apportion the 435 seats in the United States House of Representatives following the completion of each decennial census.
Schulze STV is a draft single transferable vote (STV) ranked voting system designed to achieve proportional representation. It was invented by Markus Schulze, who developed the Schulze method for resolving ties using a Condorcet method. Schulze STV is similar to CPO-STV in that it compares possible winning candidate pairs and selects the Condorcet winner. It is not used in parliamentary elections.
An electoral 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.
In mathematics and social choice, apportionment problems are a class of fair division problems where the goal is to divide (apportion) a whole number of identical goods fairly between multiple groups with different entitlements. The original example of an apportionment problem involves distributing seats in a legislature between different federal states or political parties. However, apportionment methods can be applied to other situations as well, including bankruptcy problems, inheritance law, manpower planning, and rounding percentages.
House monotonicity is a property of apportionment methods. These are methods for allocating seats in a parliament among federal states. The property says that, if the number of seats in the "house" increases, and the method is re-activated, then no state should have fewer seats than it previously had. A method that fails to satisfy house-monotonicity is said to have the Alabama paradox.
Entitlement-ratio, weight-ratio, vote-ratio, or population-ratio monotonicity is a property of apportionment methods. It says that if the entitlement for A increases proportionally to that of B, then A should not lose any seats to B. Apportionments violating this rule are called population paradoxes; a particularly severe variant, where voting for a party causes it to lose seats, is called a no-show paradox.
Seat bias is a property describing methods of apportionment. These are methods used to allocate seats in a parliament among federal states or among political parties. A method is biased if it systematically favors small parties over large parties, or vice versa. There are several mathematical measures of bias, which can disagree slightly.
Vote-ratio monotonicity (VRM) is a property of apportionment methods, which are methods of allocating seats in a parliament among political parties. The property says that, if the ratio between the number of votes won by party A to the number of votes won by party B increases, then it should NOT happen that party A loses a seat while party B gains a seat.
Balance or balancedness is a property of apportionment methods, which are methods of allocating identical items between among agens, such as dividing seats in a parliament among political parties or federal states. The property says that, if two agents have exactly the same entitlements, then the number of items they receive should differ by at most one. So if two parties win the same number of votes, or two states have the same populations, then the number of seats they receive should differ by at most one.
Static population-monotonicity, also called concordance, says that a party with more votes should not receive a smaller apportionment of seats. Failures of concordance are often called electoral inversions or majority reversals.
