Random ballot
Encyclopedia
The random ballot is a hypothetical voting method; in an election
or referendum
, the ballot of a single voter is selected at random, and that ballot decides the result of the election. In this way, each candidate or option wins with a probability exactly equal to the fraction of the electorate favouring that candidate or option.
The random ballot method is decisive, in that there is no possibility of a tied vote, assuming that the selected voter has expressed a preference (if not then another ballot can be selected at random). It is unbiased in that the probability
of a particular result is equal to the proportion of total support that that result has in all the votes. It is also strategy-free in that there is no advantage in tactical voting
. But it is not deterministic, in that a different random selection could have produced a different result, and it does not conform to majority
rule since there is a substantial possibility that the selected voter may be in the minority
.
Random ballot is most often used to explain some of the properties of other voting methods, and it is occasionally used in real life as a tiebreaker for other methods.
This system has been advocated for use by US Law professor Akhil Reed Amar
.
A related system was hypothesized by Isaac Asimov
in his short story "Franchise" (1955: reprinted in Earth is Room Enough, Doubleday, 1957), where a single voter is chosen to decide each election. However, in Asimov's thought-experiment, the "elector" is not randomly selected, but chosen by computer to be as representative as possible of the populace at large. Asimov intended this story as a parody of opinion polling
.
There is an element of randomness (other than tie-breaking) in some existing electoral systems, in two ways:
A random ballot elects a representative by choosing a ballot at random; sortition
is similar but elects individuals directly by lot, as if each ballot involved individuals voting for themselves.
Election
An election is a formal decision-making process by which a population chooses an individual to hold public office. Elections have been the usual mechanism by which modern representative democracy operates since the 17th century. Elections may fill offices in the legislature, sometimes in the...
or referendum
Referendum
A referendum is a direct vote in which an entire electorate is asked to either accept or reject a particular proposal. This may result in the adoption of a new constitution, a constitutional amendment, a law, the recall of an elected official or simply a specific government policy. It is a form of...
, the ballot of a single voter is selected at random, and that ballot decides the result of the election. In this way, each candidate or option wins with a probability exactly equal to the fraction of the electorate favouring that candidate or option.
The random ballot method is decisive, in that there is no possibility of a tied vote, assuming that the selected voter has expressed a preference (if not then another ballot can be selected at random). It is unbiased in that the probability
Probability
Probability is ordinarily used to describe an attitude of mind towards some proposition of whose truth we arenot certain. The proposition of interest is usually of the form "Will a specific event occur?" The attitude of mind is of the form "How certain are we that the event will occur?" The...
of a particular result is equal to the proportion of total support that that result has in all the votes. It is also strategy-free in that there is no advantage in tactical voting
Tactical voting
In voting systems, tactical voting occurs, in elections with more than two viable candidates, when a voter supports a candidate other than his or her sincere preference in order to prevent an undesirable outcome.It has been shown by the Gibbard-Satterthwaite theorem that any voting method which is...
. But it is not deterministic, in that a different random selection could have produced a different result, and it does not conform to majority
Majority
A majority is a subset of a group consisting of more than half of its members. This can be compared to a plurality, which is a subset larger than any other subset; i.e. a plurality is not necessarily a majority as the largest subset may consist of less than half the group's population...
rule since there is a substantial possibility that the selected voter may be in the minority
Minority group
A minority is a sociological group within a demographic. The demographic could be based on many factors from ethnicity, gender, wealth, power, etc. The term extends to numerous situations, and civilizations within history, despite the misnomer of minorities associated with a numerical statistic...
.
Random ballot is most often used to explain some of the properties of other voting methods, and it is occasionally used in real life as a tiebreaker for other methods.
This system has been advocated for use by US Law professor Akhil Reed Amar
Akhil Reed Amar
Akhil Reed Amar is an American legal scholar, an expert on constitutional law and criminal procedure. Having been the Southmayd Professor of Law at Yale Law School, he was named the Sterling Professor of Law there in 2008...
.
A related system was hypothesized by Isaac Asimov
Isaac Asimov
Isaac Asimov was an American author and professor of biochemistry at Boston University, best known for his works of science fiction and for his popular science books. Asimov was one of the most prolific writers of all time, having written or edited more than 500 books and an estimated 90,000...
in his short story "Franchise" (1955: reprinted in Earth is Room Enough, Doubleday, 1957), where a single voter is chosen to decide each election. However, in Asimov's thought-experiment, the "elector" is not randomly selected, but chosen by computer to be as representative as possible of the populace at large. Asimov intended this story as a parody of opinion polling
Polling
Polling is a municipality in the district of Mühldorf in Bavaria in Germany....
.
There is an element of randomness (other than tie-breaking) in some existing electoral systems, in two ways:
- It is often observed that candidates who are placed in a high position on the ballot-paper will receive extra votes as a result, from voters who are apathetic (especially in elections with compulsory votingCompulsory votingCompulsory voting is a system in which electors are obliged to vote in elections or attend a polling place on voting day. If an eligible voter does not attend a polling place, he or she may be subject to punitive measures such as fines, community service, or perhaps imprisonment if fines are unpaid...
) or who have a strong preference for a party but are indifferent among individual candidates representing that party (when there are two or more). For this reason, many societies have abandoned traditional alphabetical listing of candidates on the ballot in favour of either ranking by the parties (e.g., the Australian SenateAustralian SenateThe Senate is the upper house of the bicameral Parliament of Australia, the lower house being the House of Representatives. Senators are popularly elected under a system of proportional representation. Senators are elected for a term that is usually six years; after a double dissolution, however,...
), placement by lot, or rotation (e.g., Hare-Clark STV-PR system used in TasmaniaTasmaniaTasmania is an Australian island and state. It is south of the continent, separated by Bass Strait. The state includes the island of Tasmania—the 26th largest island in the world—and the surrounding islands. The state has a population of 507,626 , of whom almost half reside in the greater Hobart...
and the Australian Capital TerritoryAustralian Capital TerritoryThe Australian Capital Territory, often abbreviated ACT, is the capital territory of the Commonwealth of Australia and is the smallest self-governing internal territory...
. When candidates are ordered by lot on the ballot, the advantage of donkey voting can be decisive in a close race. - In some Single Transferable VoteSingle transferable voteThe single transferable vote is a voting system designed to achieve proportional representation through preferential voting. Under STV, an elector's vote is initially allocated to his or her most preferred candidate, and then, after candidates have been either elected or eliminated, any surplus or...
(STV) systems of proportional representationProportional representationProportional representation is a concept in voting systems used to elect an assembly or council. PR means that the number of seats won by a party or group of candidates is proportionate to the number of votes received. For example, under a PR voting system if 30% of voters support a particular...
, an elected candidate's surplus of votes over and above the quotaDroop QuotaThe Droop quota is the quota most commonly used in elections held under the Single Transferable Vote system. It is also sometimes used in elections held under the largest remainder method of party-list proportional representation . In an STV election the quota is the minimum number of votes a...
is transferred by selecting the required number of ballot papers at random. Thus, if the quota is 1,000 votes, a candidate who polls 1,200 first preference votes has a surplus of 200 votes that s/he does not need. In some STV systems (IrelandRepublic of IrelandIreland , described as the Republic of Ireland , is a sovereign state in Europe occupying approximately five-sixths of the island of the same name. Its capital is Dublin. Ireland, which had a population of 4.58 million in 2011, is a constitutional republic governed as a parliamentary democracy,...
since 1922, and AustraliaAustraliaAustralia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
from 1918 to 1984), electoral officials select 200 ballot-papers randomly from the 1,200. However, this has been criticised since it is not replicable if a recount is required. As a result, Australia has adopted a variant of fractional transfer, a.k.a. the "Gregory method", by which all 1,200 ballot-papers are transferred but are marked down in value to 0.1666 (one-sixth) of a vote each. This means that 1,000 votes "stay with" the elected candidate, while the value of the 1,200 ballot-papers transferred equals only 200 votes.
A random ballot elects a representative by choosing a ballot at random; sortition
Sortition
In politics, sortition is the selection of decision makers by lottery. The decision-makers are chosen as a random sample from a larger pool of candidates....
is similar but elects individuals directly by lot, as if each ballot involved individuals voting for themselves.