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dc.contributor.authorStensholt, Eivind
dc.date.accessioned2020-06-23T11:14:47Z
dc.date.available2020-06-23T11:14:47Z
dc.date.issued2020-06-23
dc.identifier.issn1500-4066
dc.identifier.urihttps://hdl.handle.net/11250/2659146
dc.description.abstractStruggles over the single-seat preferential election method IRV (Instant Runoff Voting) go on in public arenas and scientific journals, with focus on two “anomalies”. “Monotonicity failures” are preference distributions that allow a startling strategic voting called Pushover or its reverse. Analysis shows how a Pushover action works, and why it is hard to predict and exploit an opportunity. While not rare, monotonicity failures should be seen as a minor nuisance. “No-Show paradoxes” are alarms. The IRV tally eliminates a very clear Condorcet winner in a realistic, but somewhat unusual preference structure, too close to Duncan Black’s Single- Peak condition: Too many YXZ-ballots let Z win instead of a very clear Condorcet-winner X who is eliminated; this harms IRV’s legitimacy. Baldwin’s elimination rule when three candidates remain is a suggested remedy. Preference distributions with the same IRV-tally are grouped together and analyzed with “pictograms” as a tool. That allows a generalization of Black’s Single-Peak condition; real cases are close to “Perfect Pie-sharing”, which explains why Condorcet cycles are rare.en_US
dc.language.isoengen_US
dc.publisherFORen_US
dc.relation.ispartofseriesDiscussion paper;6/20
dc.subjectInstant Runoff Votingen_US
dc.subjectCondorcet methodsen_US
dc.subjectDuncan Black’s Single-Peak conditionen_US
dc.subjectBaldwin’s elimination ruleen_US
dc.titleAnomalies of Instant Runoff Votingen_US
dc.typeWorking paperen_US
dc.source.pagenumber40en_US


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