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Approval voting: Difference between revisions
Copied block of intro from w:Approval voting ( specifically, this version: https://en.wikipedia.org/w/index.php?title=Approval_voting&oldid=1036612916 ). I plan to do some more copyediting this evening (and not leave it like this).
(→Footnotes: Fixing links to Steven Brams' & Dudley Herschbach's "The Science of Elections", and putting archive.org link to FairVote's rebuttal) |
(Copied block of intro from w:Approval voting ( specifically, this version: https://en.wikipedia.org/w/index.php?title=Approval_voting&oldid=1036612916 ). I plan to do some more copyediting this evening (and not leave it like this).) |
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{{wikipedia}}
[[File:Approval ballot.svg|thumb|right|On an approval ballot, the voter can select any number of candidates.]]
'''Approval voting''' is a single-winner [[electoral system]] where each voter may select ("approve") any number of candidates. The winner is the most-approved candidate.
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(<small>brief intro above copied from Wikipedia<ref>Introduction copied from Wikipedia's [[Approval voting]] article ([https://en.wikipedia.org/w/index.php?title=Approval_voting&oldid=967925338 oldid=967925338])</ref></small>)
[[File:Approval ballot.svg|thumb|right|On an approval ballot, the voter can select any number of candidates.]]'''Approval voting''' is an [[electoral system]] where each voter may select ("approve") any number of candidates, and the winner is the candidate approved by the largest number of voters. It is distinct from [[plurality voting]], in which a voter may choose only one option among several, whereby the option with the most votes is chosen. It is related to [[score voting]] in which voters give each option a score on a scale, and the option with the highest total of scores is selected. Approval voting can also be used in multiwinner elections; see [[multiwinner approval voting]].
Proposals to implement approval voting for municipal elections in the United States, were approved in referendums in Fargo, North Dakota, in 2018, and St. Louis, Missouri, in 2020. 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> and St. Louis used it to advance two candidates in March 2021 [[2021 St. Louis mayoral election|nonpartian primaries for]] mayor and aldermen.<ref>{{Cite web|last=Rakich|first=Nathaniel|date=2021-03-01|title=In St. Louis, Voters Will Get To Vote For As Many Candidates As They Want|url=https://fivethirtyeight.com/features/in-st-louis-voters-will-get-to-vote-for-as-many-candidates-as-they-want/|access-date=2021-03-04|website=FiveThirtyEight|language=en-US}}</ref><ref name=":0">{{Cite web|title=March 2, 2021 Non-Partisan Primary Municipal Election|url=https://www.stlouis-mo.gov/government/departments/board-election-commissioners/elections/election.cfm?customel_datapageid_524494=852866|url-status=live|access-date=2021-03-04|website=City of St. Louis Board of Election Commissioners|language=en}}</ref>
==Procedures==
{{Wikipedia}}
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*Memphis: 42 total votes
*Nashville: 68 total votes
* Chattanooga: 58 total votes
*Knoxville: 32 total votes
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Approval voting passes a form of the [[monotonicity criterion]], in that voting for a candidate never lowers that candidate's chance of winning. Indeed, there is never a reason for a voter to [[tactical voting|tactically vote]] for a candidate X without voting for all candidates he or she prefers to candidate X. Approval voting satisfies the [[monotonicity criterion]], the [[participation criterion]], the [[Consistency Criterion]], the [[summability criterion]], the [[Weak Defensive Strategy criterion]], [[Independence of irrelevant alternatives]], the [[Non-compulsory support criterion]] and the [[Independence of equivalent candidates criterion]].
===Some Strategy for Voters
As approval voting does not offer a single method of expressing sincere preferences, but rather a plethora of them, voters are encouraged to analyze their fellow voters' preferences and use that information to decide which candidates to vote for. Some strategies include:
#Vote for every candidate you prefer to the leading candidate, and to also vote for the leading candidate if that candidate is preferred to the current second place candidate.
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*Increasing options for voters, when compared with the common [[First-past-the-post election system|first-past-the-post system]], could increase voter turnout
*It provides less incentive for [[negative campaigning]] than many other systems.
*It allows voters to express [[tolerances versus preferences|tolerances but not preferences]]. Some political scientists consider this a major advantage, especially where acceptable choices are more important than popular choices.
===Multiple winners===
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All four ballots are interchangeable. The more structured ballots may aid voters in offering clear votes so they explicitly know all their choices. The Yes/No format can help to detect an "undervote" when a candidate is left unmarked, and allow the voter a second chance to confirm the ballot markings are correct.
==
Approval voting is a simple way to make decisions in small groups without the flaws of FPTP:
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As mentioned in the video, Approval voting can be calculated by mentioning each option or candidate's name, and asking the voters to raise their hands if they support that option/candidate. The option that got the most hands raised in its favor wins. ([[Score voting]] could potentially be done if voters were allowed to raise, say, anywhere from 0 to 5 fingers, or had specially colored cards that they could raise that indicated how many points they wanted to give each option).
==
Approval voting passes [[Favorite Betrayal]], so unlike [[Choose-one FPTP voting]], it never hurts a voter to support their favorite. Example where that makes a difference:
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However, there is potential for what is known as the [[Chicken dilemma|chicken dilemma]], where one majority subfaction withholds support for the other subtraction to help its candidate win rather than the other subfaction's candidate.
===
Approval voting is also called set voting or unordered voting, because a voter expresses on their ballot the set of candidates that they prefer above all others, but is not allowed to rank (order) the candidates from 1st to 2nd to 3rd to... to last. In other words, it only allows voters to rank all candidates either 1st or last.
===
See [[Number of supportable candidates in various voting methods]]. One of the major implications of Approval voting in relation to [[choose-one FPTP voting]] is that with Approval, there is no way to tell (solely with the vote totals for each candidate) whether a voter who supported one candidate did or didn't support another. For example, in FPTP (assuming no equal ranking was allowed, a la [[cumulative voting]]), if Obama gets 30 votes and Romney gets 20, then it is guaranteed that none of the 30 voters who supported Obama also supported Romney, and vice versa. But with Approval, it is possible (albeit unlikely in this example) that everyone who voted for Romney also voted for Obama, and that Obama really only has 10 voters who support him but not Romney. This means that proportional forms of Approval voting are not as precinct-summable as the proportional form of FPTP, [[SNTV]], because not only must one know how many voters approved each candidate to calculate the winner(s) in Approval PR methods, but also which candidates each ballot approved. With choose-one ballots, knowledge of the former yields knowledge of the latter.
===
The [[Pairwise counting#Negative vote-counting approach]] approach is based on Approval voting.
<br />
====
The Approval voting winner is also always someone from the [[Smith set]] if voters' preferences truly are dichotomous (i.e. they don't have ranked preferences, but rather, honestly only support or oppose each candidate).
====
Fully strategic Approval voting with perfectly informed voters generally elects the [[Condorcet winner]], and more generally, someone from the Smith set; this is because a plurality of voters have an incentive to set their [[Approval threshold|approval thresholds]] between the Smith candidate and the most-viable non-Smith candidate, resulting in at least the same approval-based margin as the Smith candidate has in their [[head-to-head matchup]] against the non-Smith candidate. A common argument for Approval>[[Condorcet methods]] is that when voters are honest, they get a utilitarian outcome, while if they are strategic, they at least get the CW. This is not as much the case with [[Score voting]] or [[STAR voting]], but it is not possible to figure out who the CW is from Approval ballots, since only limited [[pairwise counting]] information can be inferred.
==== Using pairwise counting to find the result ====
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|-
|40
| 2nd
|A
| 10 (-10 Loss)
| ---
| 40 (Tie)
|'''30 (+10 Win)'''
|'''30 (+30 Win)'''
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|-
|30
| 3rd
|E
|10 (-40 Loss)
|20 (-10 Loss)
| 10 (-10 Loss)
| ---
|'''20 (+20 Win)'''
|-
|10
| 4th
|D
|10 (-40 Loss)
|0 (-30 Loss)
|10 (-30 Loss)
|0 (-10 Loss)
| ---
|}
This could also be done by treating each voter's Approval ballot as a ranked ballot where all approved candidates are equally ranked 1st and all other candidates are ranked last. This shows how Approval can be thought of as a Condorcet method where every candidate must be ranked either 1st or last.
====
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 guaranteeably have more approvals (specifically, they will have at least as high an approval-based margin as they do in their pairwise margin over the other candidate). Note however that they can '''not''' always make the pairwise winner of the matchup, or a candidate preferred more than or equally to the pairwise winner by any of the voters who prefer the pairwise winner over the pairwise loser, win. This is most easily seen in [[chicken dilemma]]-type situations; see [[Equilibrium#Notes]] for an example. However, this is true when the winner of the pairwise matchup [[majority-beat]]<nowiki/>s all other candidates.
==See also==
*
*
*
*
*[[Explicit approval voting]]
*[[W:Combined approval voting|Combined approval voting]]
==
*[http://bcn.boulder.co.us/government/approvalvote/ Approval Voting Home Page]
*[http://approvalvoting.org/ Citizens for Approval Voting]
*[http://approvalvoting.com/ Americans for Approval Voting]
*"[https://science.sciencemag.org/content/292/5521/1449.full
*[https://web.archive.org/web/20020429040757/http://www.fairvote.org/op_eds/science2001.htm Rebuttal to "The Science of Elections"], Center for Voting and Democracy.
=== References
<references />
{{fromwikipedia}}
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