Approval voting: Difference between revisions
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{{see also|Approval ballot}}
{{wikipedia}}
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==Usage==
Approval voting has been and is
* [[Fargo, North Dakota|'''Fargo, North Dakota''']] (as of 2018) — Fargo used approval voting in June 2020 to elect two at-large seats on its city council,<ref name="Ballotpedia Fargo">[https://ballotpedia.org/Fargo,_North_Dakota,_Measure_1,_Approval_Voting_Initiative_(November_2018) Fargo, North Dakota, Measure 1, Approval Voting Initiative (November 2018)], November 7, 2018 ''[[Ballotpedia]]''</ref><ref name="Fargo approves">[https://ivn.us/2018/11/06/one-americas-famous-towns-becomes-first-nation-adopt-approval-voting/ One of America’s Most Famous Towns Becomes First in the Nation to Adopt Approval Voting] {{Webarchive|url=https://web.archive.org/web/20181107185459/https://ivn.us/2018/11/06/one-americas-famous-towns-becomes-first-nation-adopt-approval-voting/|date=2018-11-07}}, accessed November 7, 2018</ref><ref name="Fargo votes">{{cite web |url=https://www.publicnewsservice.org/2020-06-10/civic-engagement/fargo-becomes-first-u-s-city-to-try-approval-voting/a70495-1 |title=Fargo Becomes First U.S. City to Try Approval Voting |last=Moen |first=Mike |date=June 10, 2020 |work=Public News Service |access-date=December 3, 2020 }}</ref><ref name="St. Louis approves">{{cite web|last=|first=|date=November 4, 2020|title=St. Louis Voters Approve Nonpartisan Elections|url=https://www.usnews.com/news/best-states/missouri/articles/2020-11-04/st-louis-voters-approve-nonpartisan-elections|url-status=live|archive-url=|archive-date=|access-date=December 3, 2020|work=US News and World Report}}</ref>
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*Knoxville: 32 total votes
==Criterion
Approval voting satisfies the [[unanimous consensus criterion]] and [[greatest possible consensus criterion]]. It is strongly promoted by advocates of consensus democracy for single-winner elections.
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*Chattanooga: 32
*Knoxville: 32
==== Indeterminacy of outcome ====
In certain elections, honest voters merely varying the cut-off where they give approval can lead to any particular candidate winning.<ref>{{Cite journal|last=Saari|first=Donald G.|last2=Jill|first2=Van Newenhizen|year=1988|title=The problem of indeterminancy in approval, multiple, and truncated voting systems|journal=Public Choice|volume=59|issue=2|pages=101–120|doi=10.1007/BF00054447|jstor=30024954}}</ref> Consider an election with 15 voters deciding among three candidates (A, B, C). The voters have the preferences
{|
|{A: 2, B: 1, C: 0} × 6
|-
|{B: 2, C: 1, A: 0} × 5
|-
|{C: 2, B: 1, A: 0} × 4.
|}
Even if all voters vote honestly, any candidate can win, dependent on which voters choose to approve a second candidate. If no voters approve of a second candidate, A wins. If CBA voters approve of C and B, and the other voters only approve their favorite, then B wins. If all BCA voters approve of B and C, and the other voters only approve their favorite, then C wins. Thus, as noted above, in such elections, voters have an incentive to strategically vary the number of candidates they approve of.
Approval voting advocates say this is a positive feature of approval voting, saying that the above example "demonstrates that AV responds positively to distinctions voters make among candidates that ordinal preference rankings do not mirror".<ref>{{Cite journal|last=Brams|first=Steven J.|last2=Fishburn|first2=Peter C.|last3=Merrill|first3=Samuel|author-mask3=Merrill, Samuel, III|year=1988|title=The responsiveness of approval voting: Comments on Saari and Van Newenhizen|journal=Public Choice|volume=59|pages=121–131|doi=10.1007/BF00054448}}</ref> That is, approval voting allows voters to better express their degree of approval. One example of such a situation is where we replace the CBA voter preferences with {C: 2.1, B: 2, A: 0}; in this case, it would be appropriate for B to win, as the CBA voters think C and B nearly equivalent.
Richard Niemi argues that since approval voting may elect any of a large number of candidates under strategy with non-dichotomous preferences, the method "almost begs voters to behave strategically", as the outcome depends on just what kind of strategy is used.<ref name="Niemi 1984 pp. 952–958">{{cite journal | last=Niemi | first=Richard G. | title=The Problem of Strategic Behavior under Approval Voting | journal=The American Political Science Review | publisher=[American Political Science Association, Cambridge University Press] | volume=78 | issue=4 | year=1984 | issn=00030554, 15375943 | jstor=1955800 | pages=952–958 | url=http://www.jstor.org/stable/1955800 | access-date=2022-07-03}}</ref>
==Effect on elections==
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====Strategically electing a pairwise-preferred candidate====
Supposing rational voters (see [[Approval cutoff#Rationality restrictions]] for examples; chiefly, supposing voters who equally prefer two candidates approve both or neither of them), voters can "simulate" a [[head-to-head matchup]] in Approval voting in the sense that if, between two candidates, the voters who prefer the candidate who pairwise wins the matchup move their [[approval threshold]] between the two candidates, then they can guarantee that the candidate who pairwise loses the matchup is not elected (or if there was a pairwise tie between the two candidates, then they can guarantee a tie between the two candidates). This is because all voters who equally prefer the two candidates will not create an approval-based margin between the two candidates, and because there are more voters who prefer the pairwise winner of the matchup over the other candidate, the pairwise winner will
==See also==
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[[Category:Single-winner voting methods]]
[[Category:Approval
[[Category:Favorite betrayal criterion]]
[[Category:Binary voting methods]]
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[[Category:Self-referential Smith-efficient Condorcet methods]]
[[Category:Monotonic electoral systems]]
[[Category:No-favorite-betrayal electoral systems]]
[[Category:Clone-independent electoral systems]]
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