single transferable vote

single transferable vote
Name	Single Transferable Vote
Uses	Multi-member districts
Seats voted for	Multiple
Structure	Proportional representation
Voting	Ranked voting
Rounds	1 (with transfers)
First use	Denmark (1855)
Example	Dáil Éireann elections

single transferable vote. The single transferable vote is a proportional representation voting system designed for multi-member districts. Voters rank candidates in order of preference, and a mathematical formula, the Droop quota, is used to determine election thresholds. The system aims to minimize wasted votes by transferring surplus votes from elected candidates and eliminating the weakest contenders, thereby ensuring broad representation. It is a form of preferential voting and is closely related to the instant-runoff voting method used in single-winner elections.

Description

The single transferable vote operates within electoral areas that elect several representatives, such as the Legislative Council of Hong Kong or the Australian Senate. Its core principle is that any candidate who reaches a specified quota of votes is deemed elected. This quota is typically calculated using the Hare quota or the more common Droop quota, named for Henry Richmond Droop. Surplus votes beyond this quota are not wasted but are transferred to other candidates according to the voters' subsequent preferences. This transfer process continues in rounds until all seats are filled, promoting a high degree of proportionality and allowing for the election of candidates from smaller parties or independent politicians, as seen in elections for the Northern Ireland Assembly.

History

The conceptual foundations of the single transferable vote were developed in the 19th century. The system was independently conceived by Thomas Hare in England and Carl Andræ in Denmark. Andræ first implemented a version for elections to the Rigsraadet in 1855. The method was later championed by political reformers like John Stuart Mill and was adopted for university constituencies under the Parliament of the United Kingdom. Its use expanded in the early 20th century, notably in Ireland following the establishment of the Irish Free State, where it was used to elect Dáil Éireann. The system has been a subject of study by organizations like the Electoral Reform Society.

Voting method

The voting procedure begins with voters receiving a ballot listing all candidates, as in elections for the Tasmanian House of Assembly. Each voter ranks the candidates numerically (1, 2, 3...). The count starts by establishing the quota, often using the formula associated with Henry Richmond Droop. All first-preference votes are tallied, and any candidate meeting or exceeding the quota is elected. Their surplus votes, determined by a sample or fractional method, are transferred to the next preferred candidates on those ballots. If no candidate reaches the quota, the candidate with the fewest votes is eliminated, and their votes are transferred. This cycle of surplus vote transfers and eliminations, managed by officials like those in the Australian Electoral Commission, continues until all seats are filled.

Variations and related systems

Several electoral systems are derived from or related to the single transferable vote. The most direct relative is the instant-runoff voting system, used in single-member constituencies like those for the President of India. Some jurisdictions use a simplified block voting system instead. A notable variant is the Wright system, which proposes refinements to the transfer process. The Meek's method, implemented using computer algorithms in places like New Zealand for some local body elections, allows for continuous recalculations of the quota during the count. The Scottish Parliament uses the Additional Member System, which combines single-member districts with a proportional list, a different model altogether.

Usage

The single transferable vote is employed in national parliamentary elections in several countries. It is the system used for all Dáil Éireann elections in the Republic of Ireland and for the Australian Senate. It is also used for the Northern Ireland Assembly, the Maltese House of Representatives (Malta), and the Gibraltar Parliament. Beyond national legislatures, it is used in regional elections, such as for the Tasmanian House of Assembly and the Australian Capital Territory Legislative Assembly. Many private organizations, including the Academy of Motion Picture Arts and Sciences for its Academy Awards final ballot, also utilize preferential systems based on its principles.

Advantages and disadvantages

Proponents, such as the Electoral Reform Society, argue the single transferable vote provides highly proportional outcomes, reduces tactical voting, and empowers voters to express nuanced preferences among candidates from the same party, as seen in Dublin Central (Dáil constituency). It tends to foster more cooperative politics and can improve the representation of women in politics and minority groups. Critics contend that the system can be complex for voters and administrators, potentially leading to higher rates of invalid votes. It may also strengthen the role of local party organizations in candidate selection and can result in less stable executive governments, a point of debate in the history of the Irish Free State. Furthermore, the final results can depend on the specific method of transferring surplus votes.

Category:Electoral systems Category:Proportional representation electoral systems