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{{Wikipedia}}

'''Random ballot''', also known as '''random dictatorship''' or '''single stochastic vote''', is a [[voting system]] in which the first preference candidate of a ballot drawn at random is elected.

When the drawn ballot is not decisive, then additional ballots are drawn and used only to resolve the indecision of previously drawn ballots.

== Properties ==

Random Ballot satisfies the [[Plurality criterion]], [[Monotonicity criterion]], [[Participation criterion]], [[Later-no-harm criterion]], [[clone independence]], [[Favorite Betrayal criterion]], and [[Pareto criterion]].

However, Random Ballot fails the [[Mutual majority criterion|Majority criterion]], [[Condorcet criterion]], [[Smith set|Smith criterion]], and [[Strong Defensive Strategy criterion]].

Random Ballot is strategy-proof: this follows from Gibbard's 1978 theorem.

===Example===
{{Tenn_voting_example}}

Memphis wins with 42% probability, Nashville with 26%, Chattanooga 15%, and Knoxville 17%. If the Knoxville voters had instead ranked Knoxville and Chattanooga equally, then Knoxville would win with 0% probability, since it would be impossible to draw a ballot which prefers Knoxville to Chattanooga.

== Notes ==
Interestingly, RB is one of the only single-winner voting methods that is on average a [[proportional representation|proportional]] voting method when used in single-winner districts. If, for example, 30% of the voters across a nation vote for Green Party candidates, then on average 30% of the district winners will be Greens. 

Like other non-deterministic voting systems, RB generates stronger instrumental reasons for the electorate to vote than conventional deterministic voting systems.<ref name="x444">{{cite journal | last=Jacobs | first=Bob M. | last2=Heitzig | first2=Jobst | title=Should We Vote in Non-Deterministic Elections? | journal=Philosophies | publisher=MDPI AG | volume=9 | issue=4 | date=2024-07-16 | issn=2409-9287 | doi=10.3390/philosophies9040107 | doi-access=free | page=107}}</ref>

The concept of RB can be applied to other voting methods. For example, [[rated ballot]]<nowiki/>s could be used to give candidates a probability of winning proportional to the scores on the randomly drawn ballot. 

The on-average proportional representation property can be extended into an on-average PR multiwinner method by electing a random first preference, eliminating that candidate from every ballot, and repeating for as many seats as desired. If the voters vote party list style, then the mode of the method (i.e. the winning set elected most often) is the [[d'Hondt]] outcome. This method can be derandomized using [[Markov chain|Markov chains]].

== References ==
<references />

[[Category:Single-winner voting methods]]
[[Category:Single-mark ballot voting methods]]
[[Category:FPTP-based voting methods]]
[[Category:Non-deterministic voting methods]]
[[Category:No-favorite-betrayal electoral systems]]
[[Category:Randomness]]