Random ballot

Condorcet methods Positional voting Cardinal voting Quota-remainder methods Approval-based committees Fractional social choice Semi-proportional representation By ballot type Pathological response Strategic voting Paradoxes of majority rule Positive results A random ballot or random dictatorship is a randomized electoral system where the election is decided on the basis of a single randomly-selected ballot.

Random dictatorship was first described in 1977 by Allan Gibbard, who showed it to be the unique social choice rule that treats all voters equally while still being strategyproof in all situations.

[4] The rule is rarely, if ever, proposed as a genuine electoral system, as such a method (in Gibbard's words) "leaves too much to chance".

[5] However, the rule is often used as a tiebreaker to encourage voters to cast honest ballots, and is sometimes discussed as a thought experiment.

But the situation is different with RSD (when there are indifferences): If the random ballot is used to select the members of a multi-constituency body, it can create a kind of proportional representation on average across elections.

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 voting) 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 Senate), placement by lot, or rotation (e.g. the Hare-Clark STV-PR system used in Tasmania and the Australian Capital Territory).

When candidates are ordered by lot on the ballot, the advantage of donkey voting can be decisive in a close race.