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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.[1][2] A closely-related variant is called random serial (or sequential) dictatorship, which repeats the procedure and draws another ballot if multiple candidates are tied on the first 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.[3] Its application to elections was first described in 1984 by Akhil Reed Amar.[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.[6]
- ^ Sewell, Roger; MacKay, David; McLean, Iain (January 2009). "Probabilistic electoral methods, representative probability, and maximum entropy". Voting Matters. 26: 22.
A voter is picked at random and the output ordering of the election is set to be the ordering given by that voter.
- ^ Zeckhauser, Richard (1973). "Voting Systems, Honest Preferences and Pareto Optimality". American Political Science Review. 67 (3): 938–940. doi:10.2307/1958635. ISSN 0003-0554. JSTOR 1958635. S2CID 147293110.
Each individual writes the name of a candidate on a ballot. The voters' ballots are collected and placed in a revolving drum. After shuffling, a ballot is chosen at random. The name on the chosen ballot is the elected candidate.
- ^ Gibbard, Allan (1973). "Manipulation of Voting Schemes: A General Result". Econometrica. 41 (4): 592–593. doi:10.2307/1914083. ISSN 0012-9682. JSTOR 1914083. S2CID 17069971.
In other words, each voter writes his first choice on a ballot; a single ballot is drawn at random; and the choice on that ballot is selected.
- ^ Akhil Reed Amar (June 1984). "Choosing representatives by lottery voting" (PDF). Yale Law Journal. 93 (7): 1283–1308. doi:10.2307/796258. JSTOR 796258. Archived from the original (PDF) on 2006-08-31.
- ^ Gibbard, Allan (1973). "Manipulation of Voting Schemes: A General Result". Econometrica. 41 (4): 587–601. doi:10.2307/1914083. ISSN 0012-9682. JSTOR 1914083.
- ^ Akhil Reed Amar (1 January 1995). "Lottery Voting: A Thought Experiment".