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[[Image:Preferential ballot.svg|right|thumb|Example instant runoff voting ballot]] |
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{{Electoral systems}} |
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'''Instant-runoff voting''' ('''IRV'''), also known as the '''alternative vote''' ('''AV'''), is a [[voting system]] used to elect one winner from a pool of candidates using [[preferential voting]]. Voters rank candidates in order of preference, and their votes are initially allocated to their first choice candidate. If after this initial count no candidate has a majority of votes cast, the candidate with the fewest votes is eliminated and votes for that candidate are redistributed according to the voters' second preferences. This process continues until one candidate receives more than 50% of the votes, upon which they are declared the winner. |
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Instant runoff voting is used to elect members of the [[Australian House of Representatives]],<ref name="Australian Electoral Commission">http://www.aec.gov.au/</ref> the [[President of India]], members of [[Vidhan Parishad|legislative councils]] in India, the [[President of Ireland]],<ref name="International Constitutional Law">{{cite web|url=http://www.servat.unibe.ch/icl/ei00000_.html|title=Ireland Constitution, Article 12(2.3)|publisher=International Constitutional Law|year=1995|accessdate=15 February 2008}}</ref> the national parliament of [[Papua New Guinea]], and the [[House of Representatives of Fiji]].<ref name="Fiji Constitution, Section 541">{{cite web|url=http://www.servat.unibe.ch/icl/fj00000_.html|title=Fiji Constitution, Section 54(1)|date=28 July 1998|publisher=International Constitutional Law|accessdate=15 February 2008}}</ref> It is also used in Irish [[by-election]]s and for electing [[hereditary peer]]s for the [[House of Lords|British House of Lords]].<ref name="Notice of House of Lords Conservative Hereditary Peers' By-Election Notice">{{cite web| author = House of Lords | authorlink = House of Lords | url = http://www.parliament.uk/documents/lords-information-office/holnotice20100601.pdf | title = House of Lords Website}}</ref> |
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IRV is employed by several jurisdictions in the United States, including [[Portland, Maine]]; [[San Francisco]];<ref name=mpr20090510/> [[Oakland, California]];<ref name=or2010> |
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{{cite web|url=http://oaklandrising.org/campaign/instant-runoff-voting|title=Oakland Rising:Instant Runoff Voting |publisher=oaklandrising.com |year=2010 |accessdate=23 December 2010}}</ref>; [[Minneapolis, Minnesota]]; and [[Saint Paul, Minnesota]].<ref name=mpr20090510>[http://minnesota.publicradio.org/display/web/2009/05/10/instant_runoff_voting_excercises_election_judge_fingers/ "Instant runoff voting exercises election judge fingers"] Minnesota Public Radio, 10 May 2009</ref> It is used to elect the leaders of the [[Labour Party (UK)|Labour Party]] and the [[Liberal Democrats]] in the [[United Kingdom]] and the leader of the [[Liberal Party of Canada]] in a national primary<ref name="thetyee.ca">{{cite web|last=Zehr |first=Garrett |url=http://thetyee.ca/Blogs/TheHook/Federal-Politics/2009/05/02/Liberals-one-member-one-vote/ |title=Liberals adopt one-member, one-vote election system :: The Hook |publisher=Thetyee.ca |date=2 May 2009 |accessdate=6 May 2010}}</ref> and in the elections of city [[mayor]]s in a number of countries including the UK (in the variant known as [[supplementary vote]])<ref name="The Supplementary Vote SV">{{cite web|url=http://www.electoral-reform.org.uk/article.php?id=58 |title=Electoral Reform Society - Supplementary Vote |publisher=Electoral-reform.org.uk |date= |accessdate=2011-04-17}}</ref> and New Zealand.<ref name="Elections - 2007 Final Results">{{cite web|url=http://www.wellington.govt.nz/haveyoursay/elections/results/2007/final/mayorfinal.html |title=Elections – 2007 Final Results |year=2007 |publisher=[[Wellington]] city council}}</ref> |
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Many private associations also use IRV,<ref name="Organizations & Corporations">{{cite web|url=http://www.fairvote.org/?page=1964 |title=Organizations & Corporations |publisher=FairVote |date=17 March 2001 |accessdate=6 May 2010}}</ref> including the [[Hugo Award]]s for science fiction<ref name="Oscars Copy Hugos">{{cite web|url=http://www.thehugoawards.org/2009/09/oscars-copy-hugos/ |title=Oscars Copy Hugos |publisher=The Hugo Awards |date= |accessdate=6 May 2010}}</ref> and the [[Academy of Motion Picture Arts and Sciences]] in selection of the Oscar for best picture.<ref name="www.oscars.org">{{cite web|url=http://www.oscars.org/press/pressreleases/2009/20090831a.html |title=Preferential Voting Extended to Best Picture on Final Ballot for 2009 Oscars |publisher=Oscars.org |date= |accessdate=6 May 2010}}</ref> |
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==Terminology== |
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In the United States, instant-runoff voting is an umbrella term associated with ranked choice elections where multiple rounds of counting determine majority winners; recipients of the fewest votes are eliminated between rounds, and ballots count for the top-ranked candidate not yet eliminated. The term "instant runoff" is used because the method approximates a series of runoff elections tallied in rounds, as in an exhaustive ballot election,<ref name="publications.parliament.uk">{{cite web|url=http://www.publications.parliament.uk/pa/cm200001/cmselect/cmproced/40/4005.htm|title=Second Report: Election of a Speaker|date=15 February 2001|publisher=House of Commons Select Committee on Procedure|accessdate=18 February 2008}}<!--This ref describes similarities/differences between IRV and exhaustive ballot.--></ref> except voters may not change their preference between rounds. |
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Instant runoff voting has a number of other names, often tied to countries where it is used. In the United States, most observers call it instant runoff voting because of its resemblance to [[Two-round system|runoff voting]]. It is usually referred to as the "alternative vote" (its oldest name) in the UK. Because it is a form of [[preferential voting]], IRV is also referred to simply as "ranked choice voting" in the United States and the "preferential ballot" or "preferential voting" in Canada and Australia; however it is not the only voting system based on ranked ballots. It has occasionally been referred to as '''Ware's method''', after its American inventor, [[William Robert Ware]]. |
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[[North Carolina]] law uses "instant runoff" to describe the contingent vote or "batch elimination" form of IRV in one-seat elections. A single second round of counting produces the top two candidates for a runoff election.<ref>{{cite web|url=http://www.ncleg.net/enactedlegislation/sessionlaws/html/2005-2006/sl2006-192.html |title=S.L. 2006-192 |publisher=Ncleg.net |date= |accessdate=6 May 2010}}</ref> Election officials in [[Hendersonville, North Carolina]] use "instant runoff" to describe a multi-seat election system that attempts to simulate in a single round of voting their previous system of multi-seat runoffs.<ref>{{cite web|url=http://blogs.citizen-times.com/blogs/index.php?blog=10&title=no_instant_runoff_in_hendersonville&more=1&c=1&tb=1&pb=1 |title=CITIZEN-TIMES: Capital Letters – Post details: No instant runoff in Hendersonville |publisher=Blogs.citizen-times.com |date= |accessdate=6 May 2010}}</ref> State law in [[South Carolina]]<ref>[http://www.scstatehouse.net/sess116_2005-2006/bills/3720.doc ]{{dead link|date=April 2011}}</ref> and [[Arkansas]]<ref>[http://www.arkleg.state.ar.us/ftproot/bills/2005/public/HB1770.pdf ]{{Dead link|date=May 2010}}</ref> use "instant runoff" to describe the practice of having certain categories of absentee voters cast ranked ballots before the first round of a runoff that are then counted in a runoff election. |
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When the [[single transferable vote]] (STV) system is applied to a single-winner election it becomes IRV. For this reason IRV is sometimes considered to be merely a limited form of STV. However, IRV is usually excluded from discussions of STV, because STV was designed for multi-seat [[constituency|constituencies]], redistributes votes from both the top (winners) and bottom (dropped candidates), and produces broadly proportional results (depending on the number of seats per constituency); none of which need apply to IRV. |
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==History== |
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{{Main|History and use of instant-runoff voting}} |
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Instant runoff voting was devised in 1871 by American [[architect]] [[William Robert Ware]],<ref>{{cite web|author=Wellfire Interactive |url=http://www.fairvote.org/articles/reilly.pdf |title=Articles |publisher=FairVote.org |date= |accessdate=2011-04-17}}</ref> although it is, in effect, a special case of the [[single transferable vote]] system, which emerged independently in the 1850s. Unlike the single transferable vote in multi-seat elections, however, the only ballot transfers are from backers of candidates who have been eliminated. |
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The first known use of an IRV-like system in a governmental election was in 1893 in an election for the [[self-governing colony|colonial]] government of [[Queensland]], in Australia.<ref>{{cite web|url=http://www.nuffield.ox.ac.uk/Politics/papers/2002/w23/mclean.pdf|format=PDF|title=Australian electoral reform and two concepts of representation|author=McLean, Iain|date=2002-10|accessdate=22 February 2008|page=11}}</ref> The variant used for this election was a "contingent vote". IRV in its true form was first used in 1908 in a State election in [[Western Australia]]. |
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IRV was introduced nationally in Australia in 1918 after the [[Swan by-election, 1918|Swan by-election]], in response to the rise of the conservative [[National Party of Australia|Country Party]], representing small farmers. The Country Party split the anti-Labor vote in conservative country areas, allowing Labor candidates to win on a minority vote. The conservative government of [[Billy Hughes]] introduced preferential voting as a means of allowing competition between the two conservative parties without putting seats at risk. It was first used at the [[Division of Corangamite|Corangamite]] by-election on 14 December 1918.<ref>{{cite web|url=http://australianpolitics.com/elections/features/voting-methods-history.shtml |title=Australian Electoral History: Voting Methods |publisher=Australianpolitics.com |date= |accessdate=2011-04-17}}</ref> [[Thomas Hare (political scientist)|Thomas Hare]] and [[Andrew Inglis Clark]] had previously introduced it in the [[Tasmanian House of Assembly]]. |
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==Election procedure== |
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===Process=== |
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[[Image:IRV counting flowchart.1.png|300px|right|thumb|Flowchart for counting IRV votes]] |
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In instant runoff voting, as with other ranked election methods, each voter ranks the list of candidates in order of preference. Under a common [[Preferential voting#Ballot variations|ballot]] layout, the voter marks a '1' beside the most preferred candidate, a '2' beside the second-most preferred, and so forth, in [[ascending order]].{{Clarify|date=March 2011}} |
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The mechanics of the process are the same regardless of how many candidates the voter ranks, and how many are left unranked. In some implementations, the voter ranks as many or as few choices as they wish, while in other implementations the voter is ''required'' to rank either all candidates, or a prescribed number of them. |
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[[Image:Hand marking ranked ballot.JPG|thumb| left|[[Optical scan voting system|Optical scan]] IRV ballot]] |
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In the initial count, the first preference of each voter is counted and used to order the candidates. Each first preference counts as one vote for the appropriate candidate. Once all the first preferences are counted, if one candidate holds a [[majority]], that candidate wins. Otherwise the candidate who holds the fewest first preferences is eliminated. If there is an exact tie for last place in numbers of votes, [[#Handling ties|tie-breaking rules]] determine which candidate to eliminate. Some jurisdictions eliminate all low-ranking candidates simultaneously whose combined number of votes is fewer than the number of votes received by the lowest remaining candidates. |
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Ballots assigned to eliminated candidates are recounted and assigned to one of the remaining candidates based on the next preference on each ballot. The process repeats until one candidate achieves a majority of votes cast for continuing candidates. Ballots that |
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'exhaust' all their preferences (all its ranked candidates are eliminated) are set aside. |
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===Ballots=== |
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As seen above, voters in an IRV election rank candidates on a [[preferential voting|preferential ballot]]. IRV systems in use in different countries vary both as to ballot design and as to whether or not voters are obliged to provide a full list of preferences. In elections such as those for the President of Ireland and the [[New South Wales Legislative Assembly]], voters are permitted to rank as many (or as few) candidates as they wish. This is known in Australia as '''optional preferential voting'''. |
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Under optional preferential voting, voters may make only a first choice, known as "[[bullet voting]]". Allowing voters to rank only as many candidates as they wish may better reflect their preferences, but may result in [[#Ballot exhaustion|ballot exhaustion]] (where all the voters preferences are eliminated before a candidate is elected). |
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One IRV variant requires voters to express an order of preference for every candidate and thus they consider ballots that do not contain a complete ordering of all candidates to be [[spoilt vote|spoilt]]. In Australia this variant is known as 'full preferential voting'.<ref>{{cite web|url=http://www.eca.gov.au/systems/single/by_category/preferential.htm|title=Electoral Systems|publisher=Electoral Council of Australia|accessdate=15 February 2008}}</ref> This can become burdensome in elections with many candidates and can lead to '[[donkey voting]]' in which the voter simply chooses candidates at random or in top-to-bottom order. [This variant is used in [[Australian electoral system|some Australian federal elections]] and [[Electoral systems of the Australian states and territories|some state elections]]]. |
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===Candidate order on the ballot paper=== |
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The common way to list candidates on a ballot paper is alphabetically or by random lot. In some cases candidates may also be grouped by political party. Alternatively, [[Robson Rotation]] involves randomly changing candidate order for each print run.{{citation needed|date=November 2010}} |
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===Party strategies=== |
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Where preferential voting is used for the election of an assembly or council, parties and candidates often advise their supporters on their lower preferences. This can lead to "preference deals", a form of pre-election bargaining, in which smaller parties agree to direct their voters in return for support from the winning party on issues critical to the small party.{{citation needed|date=November 2010}} However, this relies on the assumption that supporters of a minor party will mark preferences for another party based on the advice that they have been given. |
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===Counting logistics=== |
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Most IRV elections have been tallied with a '''hand count','' such as elections to [[Australia]]'s House of Representatives. [[Cary, North Carolina]]'s pilot program in October 2007 adopted this approach.<ref>{{cite web|url=http://www.ncleg.net/Sessions/2005/Bills/House/HTML/H1024v7.html |title=SL2006-0192 |publisher=Ncleg.net |date= |accessdate=6 May 2010}}</ref> After counting first choices on optical scan equipment at the polls hand-counts were used for subsequent preference rounds. An IRV hand-count is more time-consuming than a [[Plurality voting system|plurality]] hand-count, and may need to occur over a number of iterations. |
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In Australia, a first preference count (and sometimes a notional two candidate preference allocation) is almost always conducted by electoral officials under the scrutiny of the candidates or their appointed scrutineers at individual polling booths immediately after polling closes. That count is communicated to the electorate returning officer (usually a paid appointee of the state or federal electoral authority conducting the poll) at a central location on the night and the actual ballot papers are secured and subsequently delivered to that official. These ballots are then checked and a final count of these ballots plus any absentee and special category ballots happens again under the scrutiny of the candidates and scrutineers at premises that have been set up for the purpose by the returning officer. This process may take several days but in any event the outcome of the election is usually known well before all ballots have been counted and preferences allocated. |
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For Presidential elections, Ireland has several dozen counting centers around the nation. Each center reports its totals and receives instructions from the central office about which candidate or candidates to eliminate in the next round of counting. For Parliamentary bye-elections, the Returning Officer for the constituency makes these decisions. |
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==Examples== |
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Some examples of IRV elections are given below. |
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===2006 Burlington mayoral election=== |
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{{See also|Instant-runoff voting in the United States#Burlington_results_2006}} |
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{| class="wikitable" style="text-align:center; float:right; margin-left:1em" |
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|- |
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!Candidate |
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!colspan=2|Round 1 |
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!colspan=2|Round 2 |
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|- |
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![[Bob Kiss]] |
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| 3,809 || ''(38.9%)'' |
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| 4,761 || ''(48.6%)'' |
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|- |
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![[Hinda Miller]] |
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| 3,106||''(31.7%)'' |
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| 3,986||''(40.7%)'' |
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|- |
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!Kevin Curley |
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| 2,609||''(26.7%)'' |
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|colspan=2 | — |
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|- |
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!Other |
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|254||''(2.6%)'' |
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|colspan=2 | — |
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|- |
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!Exhausted ballots |
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|10||''(0.1%)'' |
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|1,041||''(10.5%)'' |
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|- |
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!Total |
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|9,778||''(100%)'' |
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|9,778||''(100%)'' |
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|} |
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In 2006 the U.S. city of [[Burlington, Vermont]], held a mayoral election using instant runoff voting. Progressive [[Bob Kiss]] won in two rounds with 48.6% of the first round ballots, defeating Democrat [[Hinda Miller]] who achieved 40.7%. 10.6% (1,031) of the ballots were exhausted before the final round, because those voters (largely backers of Republican candidate Curley) offered no preference between the final two candidates, Miller and Kiss.<ref>{{cite web|url=http://www.burlingtonvotes.org/20060307/2006%20Burlington%20Mayor%20Round3.htm|title=2006 Burlington mayoral election|date=7 March 2006|publisher=Voting Solutions|accessdate=22 February 2008}}</ref> |
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After the first round, all but two candidates were eliminated, as their combined vote (2,863) was less than Miller's, so that none could pull ahead of Miller, even by receiving every vote from the other minor candidates. The votes for these candidates were recounted and redistributed between Kiss and Miller. After the second round count, Kiss was declared the winner as he had obtained a majority (54.4%) of the remaining unexhausted ballots. |
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{{-}} |
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===1990 Irish presidential election=== |
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{{See also|Irish presidential election, 1990}} |
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{|class="wikitable" style="float:right; text-align:center; margin:10px" |
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|- |
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! colspan=5|Irish presidential election, 1990<ref> |
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{{cite web |
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|url=http://www.electionsireland.org/result.cfm?election=1990P&cons=194 |
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|title=Presidential Election November 1990 |
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|work=ElectionsIreland.org |
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|accessdate=23 November 2009 |
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}}</ref> |
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|- |
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!Candidate |
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!colspan=2|Round 1 |
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!colspan=2|Round 2 |
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|- |
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![[Mary Robinson]] |
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|612,265 || ''(38.9%)'' |
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|817,830 || ''(51.6%)'' |
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|- |
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![[Brian Lenihan, Snr|Brian Lenihan]] |
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|694,484||''(43.8%)'' |
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|731,273||''(46.2%)'' |
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|- |
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![[Austin Currie]] |
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|267,902||''(16.9%)'' |
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|colspan=2 | — |
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|- |
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!Exhausted ballots |
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|9,444||''(0.6%)'' |
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|34,992||''(2.2%)'' |
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|- |
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!Total |
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|1,584,095||''(100%)'' |
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|1,584,095||''(100%)'' |
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|} |
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The result of the [[Irish presidential election, 1990|1990 Irish presidential election]] provides an example of how instant runoff voting can produce a different result than [[first-past-the-post voting]]. The three candidates were [[Brian Lenihan, Snr|Brian Lenihan]] of the traditionally dominant [[Fianna Fáil]] party, [[Austin Currie]] of the nation's now, largest party, [[Fine Gael]], and [[Mary Robinson]], nominated by the [[Labour Party (Ireland)|Labour Party]] and the [[Workers' Party of Ireland|Worker's Party]]. After the first round, Lenihan had the largest share of the first choice rankings (and hence would have won a first-past-the-post vote), but no candidate attained the necessary majority. Currie was eliminated and his votes reassigned to the next choice ranked on each ballot; in this process, Robinson received 82% of Currie's votes, thereby overtaking Lenihan.<!-- no cite: since only 3 candidates just simple ratio of extra votes in 2nd count. --> |
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{{clr}} |
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==Voting system criteria== |
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{{Main|Comparison of instant runoff voting to other voting systems#Voting system criteria}} |
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Scholars rate voting systems using mathematically-derived [[voting system criterion|voting system criteria]], which describe desirable features of a system. No ranked preference method can meet all of the criteria, because some of them are mutually exclusive, as shown by statements such as [[Arrow's impossibility theorem]] and the [[Gibbard-Satterthwaite theorem]].<ref>David Austen-Smith and Jeffrey Banks, "Monotonicity in Electoral Systems," ''American Political Science Review'', Vol 85, No 2 (Jun. 1991)</ref> The criteria that IRV meets, and those that it does not, are listed below. |
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===Majority criterion=== |
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{{Tick}} The '''[[majority criterion|majority]]''' criterion states that "if one candidate is preferred by an absolute majority of voters, then that candidate must win". IRV meets this criterion. |
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===Mutual majority criterion=== |
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{{Tick}} The '''[[mutual majority criterion|mutual majority]]''' criterion states that "if every voter prefers every member of a group of candidates to every candidate not in that group, then one of the preferred group must win". IRV meets this criterion. |
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===Later-no-harm criterion=== |
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{{Tick}} The '''[[later-no-harm criterion|later-no-harm]]''' criterion states that "if a voter alters the order of candidates lower in his/her preference (e.g. swapping the second and third preferences), then that does not affect the chances of the most preferred candidate being elected". IRV meets this criterion. |
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===Resolvability criterion=== |
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{{Tick}} The '''[[resolvability criterion|resolvability]]''' criterion states that "the probability of an exact tie must diminish as more votes are cast". IRV meets this criterion. |
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===Condorcet winner criterion=== |
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{{Cross}} The '''[[Condorcet criterion|Condorcet winner]]''' criterion states that "if a candidate would win a [[Condorcet method|head-to-head competition]] against every other candidate, then that candidate must win the overall election". IRV does not meet this criterion. |
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IRV is more likely to elect the Condorcet winner than plurality voting. The California cities of Oakland, San Francisco and San Leandro in 2010 provide an example; there were a total of four elections in which the plurality voting leader in first choice rankings was defeated, and in each case the IRV winner was the Condorcet winner, including a San Francisco election in which the IRV winner was in third place in first choice rankings.<ref>{{cite web|author=Wellfire Interactive |url=http://www.fairvote.org/understanding-the-rcv-election-results-d10 |title=Understanding the RCV Election Results in District 10 |publisher=FairVote.org |date= |accessdate=2011-04-17}}</ref> |
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===Condorcet loser criterion=== |
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{{Tick}} The '''[[Condorcet loser criterion|Condorcet loser]]''' criterion states that "if a candidate would lose a [[Condorcet method|head-to-head competition]] against every other candidate, then that candidate must not win the overall election". IRV meets this criterion. |
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===Consistency criterion=== |
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{{Cross}} The '''[[consistency criterion|consistency]]''' criterion states that "dividing the electorate into two groups and running the same election separately with each group should return the same results as the election over the whole electorate." IRV, like all preferential voting systems which are not [[positional voting system|positional]], does not meet this criterion: dividing the electorate into two groups and running the same election separately with each group is not guaranteed to return the same results as the election over the whole electorate. In a general sense, this reflects the fact that the system does not produce as evenly-spread a set of winners as a [[proportional representation|proportional]] process.<ref>http://www.fairvote.ca/files/AV-backgrounder-august2009_1.pdf</ref> |
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===Monotonicity criterion=== |
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{{Cross}} The '''[[monotonicity criterion|monotonicity]]''' criterion states that "a voter cannot harm a candidate's chances of winning by voting that candidate higher, or help a candidate by voting that candidate lower, while keeping the relative order of all the other candidates equal." As with traditional runoff elections, IRV does not meet this criterion. Allard<ref>{{cite web|author=Crispin Allard|url=http://www.mcdougall.org.uk/VM/ISSUE5/P1.HTM|title=Estimating the Probability of Monotonicity Failure in a UK General Election|date=1996-01|accessdate=2011-05-04}}</ref> claims failure is unlikely, but others <ref>{{cite web|author=Warren D. Smith|url=http://rangevoting.org/Monotone.html|title=Monotonicity and Instant Runoff Voting|accessdate=2011-05-04}}</ref> argue that the probability of monotonicity failure is greater. |
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===Participation criterion=== |
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{{Cross}} The '''[[participation criterion|participation]]''' criterion states that "the best way to help a candidate win must not be to abstain". IRV does not meet this criterion: there are some situations in which the voter's preferred candidate can be best helped if the voter does not vote at all. |
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===Reversal symmetry criterion=== |
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{{Cross}} The '''[[reversal symmetry]]''' criterion states that "reversing the order of every ballot paper must alter the final winner". IRV does not meet this criterion: it is possible to construct an election where reversing the order of every ballot paper does not alter the final winner. However, this is essentially an academic exercise. |
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===Independence of irrelevant alternatives criterion=== |
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{{Cross}} The '''[[independence of irrelevant alternatives]]''' criterion states that "the election outcome remains the same even if a candidate who cannot win decides to run." IRV does not meet this criterion; in the general case, instant-runoff voting can be susceptible to [[strategic nomination]]: whether or not a candidate decides to run at all can affect the result even if the new candidate cannot themselves win.<ref name="wds">{{cite web|url=http://rangevoting.org/Burlington.html |title=Burlington Vermont 2009 IRV mayoral election |publisher=RangeVoting.org |date= |accessdate=2011-04-17}}</ref> |
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===Independence of clones criterion=== |
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{{Tick}} The '''[[independence of clones criterion]]''' states that "the election outcome remains the same even if an identical candidate who is equally-preferred decides to run." IRV meets this criterion. |
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==Comparison to other voting systems== |
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{{main|Comparison of instant runoff voting to other voting systems}} |
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==Tactical voting== |
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===Is tactical voting possible?=== |
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{{main|Comparison of instant runoff voting to other voting systems#Tactical voting}} |
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The [[Gibbard–Satterthwaite theorem]] demonstrates that no voting system can be entirely immune from tactical voting unless it is dictatorial (there is only one person who is able to choose the winner) or incorporates an element of chance. IRV is considered to be one of the less-manipulable systems, with voting theorist [[Nicolaus Tideman]] noting that "alternative vote is quite resistant to strategy."<ref name=tac1>John J. Bartholdi III, [[James B. Orlin]] (1991) [http://www.isye.gatech.edu/~jjb/papers/stv.pdf "Single transferable vote resists strategic voting,"] ''Social Choice and Welfare,'' vol. 8, p. 341-354</ref> But the failure of IRV to meet the monotonicity, Condorcet winner, and participation criteria means that it could theoretically permit forms of tactical voting in IRV elections if voters had complete and reliable information about voters' full preferences.<ref name=tac3 /> However, [[FairVote]] claims that these possible strategies are frequently misconstrued (inadvertently or maliciously) to suggest that "Having more voters rank [a] candidate first, can cause [them] to switch from being a winner to being a loser.".<ref>{{cite web|url=http://archive.fairvote.org/?page=2261 |title=Monotonicity and IRV - Why the Monotonicity Criterion is of Little Import |publisher=Archive.fairvote.org |date= |accessdate=2011-04-17}}</ref> In fact, it is the change in lower candidates that is important: whether the votes are shifted to the leading candidate, to a fringe candidate, or are discarded altogether, is of no importance. What possible tactical voting would seek to achieve is to alter the order of eliminations in early rounds to ensure that the original winner is instead challenged by a stronger opponent in the final round. |
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The 2009 [[Burlington, Vermont mayoral election, 2009|mayoral election]] in [[Burlington, Vermont]] provides an example where strategy theoretically could have worked, but would have been unlikely in practice. In that election most supporters of the candidate who came in second (a Republican led the first-round) preferred the [[Condorcet method|Condorcet]] winner, a Democrat, to the IRV winner, the Progressive Party nominee. If about 20% of backers of the Republican candidate had insincerely raised their second-choice to first-choice, the Republican candidate would have dropped from first to third in first choices, and the Democrat would then have won the instant runoff when the Republican was eliminated.<ref name=tac3>Warren Smith (2009) [http://rangevoting.org/Burlington.html "Burlington Vermont 2009 IRV mayor election; Thwarted-majority, non-monotonicity & other failures (oops)"]</ref> Yet, since the Republican candidate nearly won the instant runoff, the voters probably would not have decided to compromise in order to get the Condorcet winner elected, as the risks would have been too great. |
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===Is tactical voting necessary?=== |
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{{main|Spoiler effect}} |
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The spoiler effect is where two or more equally-popular candidates divide the vote, meaning that each receives fewer votes than a single opponent who is disliked by the majority of voters but has little competition. Proponents of IRV note that by reducing the spoiler effect, IRV makes it safe to vote honestly for marginal parties, and so discourages [[tactical voting]]: under a plurality system, voters who sympathize most strongly with a marginal candidate are strongly encouraged to instead vote for a more popular candidate who shares some of the same principles, since that candidate has a much greater chance of being elected and a vote for the fringe candidate is largely wasted. In an IRV system this is no longer an issue since the voter can rank the marginal candidate first and the mainstream candidate second; in the likely event that the fringe candidate is eliminated, the vote is not wasted but is transferred to the second preference. In Australia's national elections in 2007, for example, the average number of candidates in a district was seven, and at least four candidates ran in every district; notwithstanding the fact that Australia only has two major political parties. Every seat was won with a majority of the vote, including several where results would have been different under plurality voting.<ref>http://results.aec.gov.au/13745/website/HouseResultsMenu-13745.htm</ref> |
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==Proportionality== |
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{{Main|Comparison of instant runoff voting to other voting systems#Voting system results}} |
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IRV is not a proportional voting system. Like all winner-take-all voting systems, IRV tends to exaggerate the number of seats won by the largest parties; small parties without majority support in any given constituency are unlikely to earn seats in a legislature, although their supporters will be more likely to be part of the final choice between the two strongest candidates.<ref>{{cite web|url=http://www.mtholyoke.edu/acad/polit/damy/BeginnningReading/types.htm |title=Types of Voting Systems |publisher=Mtholyoke.edu |date=8 April 2005 |accessdate=6 May 2010}}</ref> A simulation of IRV in the [[United Kingdom general election, 2010|2010 UK general election]] by the [[Electoral Reform Society]] concluded that the election would have altered the balance of seats between the three main parties, but the number of seats won by minor parties would have remained unchanged.<ref>{{cite news|url=http://www.guardian.co.uk/politics/2010/may/10/alternative-vote-minimal-impact-general-election|accessdate=1 April 2011|date=10 May 2010|title=Electoral reform: Alternative vote system would have had minimal impact on outcome of general election|publisher=''[[The Guardian]]''}}</ref> |
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Australia, a nation with a long record of using IRV for election of legislative bodies, has had representation in its parliament broadly similar to that expected by [[Plurality voting system|plurality systems]]. Medium-sized parties, such as the [[National Party of Australia]], can co-exist with [[Coalition (Australia)|coalition]] partners such as the [[Liberal Party of Australia]], and can compete against it without fear of losing seats to other parties due to vote splitting.<ref>[http://www.abc.net.au/elections/federal/2004/guide/prefhistory.htm History of Preferential Voting in Australia], [[Australian Broadcasting Corporation]], 2004 Election Guide. "''Such a long lasting Coalition would not have been possible under first part the post voting''"</ref> IRV is more likely to result in legislatures where no single party has an absolute majority of seats (a [[hung parliament]]),{{citation needed|date=May 2011}} but does not generally produce as fragmented a legislature as a fully-proportional system, such as is used for the [[House of Representatives of the Netherlands]] or the [[New Zealand House of Representatives]], where coalitions of numerous small parties are needed for a majority. |
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==Costs== |
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{{Main|Comparison of instant runoff voting to other voting systems#Cost}} |
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The costs of printing and counting ballot papers for an IRV election are no different from those of any other system using the same technology. However, the more-complicated counting system may encourage officials to introduce more advanced technology such as software counters or electronic voting machines. [[Pierce County, Washington]] election officials outlined one-time costs of $857,000 to implement IRV for its elections in 2008, covering software and equipment, voter education and testing.<ref>{{cite web|url=http://www.ncvoter.net/downloads/Pierce_Co_WA_2008_IRV_Recap.pdf |title=Pierce County RCV Overview – City of LA Briefing |format=PDF |date= |accessdate=6 May 2010}}</ref> In 2009 the auditor of Washington counties reported that the ongoing costs of the system were not necessarily balanced by the costs of eliminating runoffs for most county offices, because those elections may be needed for other offices not elected by IRV.<ref>{{cite web|url=https://blog.thenewstribune.com/politics/2009/05/06/pierce-county-auditor-sees-savings-from-scrapping-ranked-choice-voting/ |title=County auditor sees savings from scrapping ranked choice voting |publisher=Blogs.thenewstribune.com |date=30 August 2006 |accessdate=6 May 2010}}</ref> Other jurisdictions have reported immediate cost savings.<ref>{{cite web|url=http://archive.fairvote.org/?page=2543 |title=FairVote - Wake County Answers on IRV Election Administration |publisher=Archive.fairvote.org |date= |accessdate=2011-04-17}}</ref> |
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It is possible to count IRV ballots by hand, and this is done for the Australian federal elections. Because multiple rounds of counting are required, the ballots must either be collected in one central location, or the interim results of each count must be collated and instructions sent out to each counting centre as to what action to take next.<ref>{{cite web|url=http://electionmathematics.org/ucvAnalysis/US/RCV-IRV/InstantRunoffVotingFlaws.pdf |title=Realities mar Instant Runoff Voting |publisher=Kathy Dopp |date=12 Feb 2009 |accessdate=1 Mar 2011}}</ref> In Australia counting takes place in each polling centre individually, and the results of the first-preference votes are aggregated by telephone;<ref>{{cite web|url=http://www.aec.gov.au/Voting/counting/index.htm |title=Counting the Votes |publisher=Aec.gov.au |date=2010-12-23 |accessdate=2011-04-17}}</ref> for subsequent rounds the papers are brought to one central counting centre. |
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The perceived costs or cost savings of adopting an IRV system are commonly used by both supporters and critics. In the 2011 referendum on the Alternative Vote in the UK, the [[NOtoAV]] campaign launched with a claim that adopting the system would cost £250 million; commentators argued that this headline figure had been inflated by including £82 million for the cost of the referendum itself, and a further £130 million on the assumption that the UK would need to introduce electronic voting systems, when ministers had confirmed that there was no intention of implementing such technology, whatever the outcome of the election.<ref>{{cite web|url=http://www.bbc.co.uk/news/uk-politics-12564879 |title=No to AV campaign reject rivals' 'scare stories' claim |publisher=Bbc.co.uk |date=2011-02-24 |accessdate=2011-04-17}}</ref> Automated vote counting is seen by some to have a greater potential for election fraud;<ref>{{cite web|url=http://www.ncvoter.net |title=Nc Voter |publisher=Nc Voter |date= |accessdate=6 May 2010}}</ref> IRV supporters counter these claims with recommended audit procedures,<ref>{{cite web|url=http://www.fairvote.org/?page=2469 |title=Ranked Choice Voting and Election Integrity |publisher=FairVote |date=25 June 2008 |accessdate=6 May 2010}}</ref> or note that automated counting is not required for the system at all. |
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Because it does not require two separate votes, IRV is accepted to cost less than [[two round system|two-round]] primary/general or general/runoff election systems.<ref>http://sfpl4.sfpl.org/pdffiles/March5_2002.pdf</ref> |
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==Negative campaigning== |
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{{Main|Comparison of instant runoff voting to other voting systems#Political parties}} |
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John Russo, Oakland City Attorney, argued in the [[Oakland Tribune]] on July 24, 2006 that "Instant runoff voting is an antidote to the disease of negative campaigning.{{Citation needed|date=November 2010}} IRV led to San Francisco candidates campaigning more cooperatively. Under the system, their candidates were less likely to engage in negative campaigning because such tactics would risk alienating the voters who support 'attacked' candidates", reducing the chance that they would support the attacker as a second or third choice.<ref>[http://www.nytimes.com/2004/09/30/national/30runoff.html New Runoff System in San Francisco Has the Rival Candidates Cooperating<!-- Bot generated title -->]</ref><ref>[http://findarticles.com/p/articles/mi_qn4176/is_20060724/ai_n16641454 Oakland Tribune, John Russo]{{Dead link|date=May 2010}}</ref> |
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No formal studies have been conducted in the United States. Internationally, Benjamin Reilly suggests instant runoff voting eases ethnic conflict in divided societies.<ref>{{cite web|url=http://muse.jhu.edu/login?uri=/journals/journal_of_democracy/v013/13.2reilly.html |title=Project MUSE |publisher=Muse.jhu.edu |date= |accessdate=6 May 2010}}</ref> This feature was a leading argument for why [[Papua New Guinea]] adopted instant runoff voting.<ref>[http://aceproject.org/ero-en/regions/pacific/PG/Papua_new_guinea_leaflet.pdf/view "Papua New Guinea: Leaflet on Limited Preferential Voting System], Electoral Knowledg Network</ref> |
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Critics allege there is a lack of evidence that such an effect occurs as often as suggested.<ref>{{cite web| url = http://www.beyondchron.org/news/index.php?itemid=1468 | title = Instant Runoff Voting Not Meeting Expectations | first = John | last = Dunbar | date = 17 November 2005}}</ref> Indeed, Lord Alexander's objections to the conclusions of the British Independent Commission on the Voting System's [http://www.archive.official-documents.co.uk/document/cm40/4090/chap-9.htm report] cites the example of Australia saying "their politicians tend to be, if anything, more blunt and outspoken than our own." |
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==Plural voting== |
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{{Main|Comparison of instant runoff voting to other voting systems#Voter power}} |
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In [[Ann Arbor, Michigan]] arguments over IRV in letters to newspapers included the belief that IRV "gives minority candidate voters two votes," because some voters' ballots may count for their first choice in the first round and a lesser choice in a later round.<ref>{{cite web | url = http://www.migreens.org/hvgreens/aa-irv01.htm | title = History of Preferential Voting in Ann Arbor | first = Benjamin | last = Walter}}</ref> The argument that IRV represents [[plural voting]] is sometimes used in arguments over the 'fairness' of the system, and has led to several legal challenges in the United States. The argument was addressed and rejected by a Michigan court in 1975; in ''[[Stephenson v. the Ann Arbor Board of City Canvassers]]'', the court held "majority preferential voting" (as IRV was then known) to be in compliance with the Michigan and United States constitutions, writing: |
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{{quote|Under the 'M.P.V. System', however, no one person or voter has more than one effective vote for one office. No voter's vote can be counted more than once for the same candidate. In the final analysis, no voter is given greater weight in his or her vote over the vote of another voter, although to understand this does require a conceptual understanding of how the effect of a 'M.P.V. System' is like that of a run-off election. The form of majority preferential voting employed in the City of Ann Arbor's election of its Mayor does not violate the one-man, one-vote mandate nor does it deprive anyone of equal protection rights under the Michigan or United States Constitutions.|<ref>{{cite web|url=http://archive.fairvote.org/?page=397 |title=Ann Arbor Law Suit |publisher=FairVote |date= |accessdate=10 May 2011}}</ref>}} |
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==Invalid ballots and exhausted ballots== |
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{{Main|Comparison of instant runoff voting to other voting systems#Ballot issues}} |
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Because the ballot marking is more complex, there is an increase in spoiled ballots. The Australian ballot, for example, requires voters to write a number beside every candidate. The numbers need to be legible and cannot be repeated or skipped. Ballots that do not rank all candidates are considered spoiled, although New South Wales and Queensland count such ballots. [[Antony Green]] notes that "The exhaustion rate has approached 80% in some seats....optional preferential voting almost always assists the party with the highest primary vote."<ref>{{cite web|url=http://www.abc.net.au/elections/federal/2004/items/200407/s1162263.htm |title=Antony Green, Antony Green's Q&A ... about the political effect of optional preferential voting |publisher=Abc.net.au |date= |accessdate=6 May 2010}}</ref> However, since Australia also enforces compulsory voting (voters can be fined if they do not participate in the election), it is impossible to tell how many ballots are deliberately spoiled. Notwithstanding this difficulty, the NOtoAV campaign in the 2011 UK referendum has criticised the Alternative Vote in Australia, noting that "there are also more than five times as many spoilt ballot papers in Australia than in the UK."<ref>{{cite web|author=|url=http://www.no2av.org/why-vote-no/av-myth-busting/ |title=Busting the Myths of AV |publisher=No2av.org |date=2010-10-25 |accessdate=2011-04-17}}</ref> Australian candidates and parties often distribute "how to vote" cards to their supporters. According to the [http://aes.anu.edu.au/ Australian Election Study], 55% of voters admit to following these cards. |
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Other jurisdictions using a ranked ballot don't always require complete ranking. Many also use columns to indicate preference instead of numbers, so that one column is marked for each (preferred) candidate and there is only one candidate marked in each column. By allowing voters to rank just their favorite candidates, the concern over "less-informed preferences" may be reduced. |
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==Robert's Rules of Order== |
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{{Main|Comparison of instant runoff voting to other voting systems#Rules of Order}} |
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The sequential elimination method used by IRV is described in ''[[Robert's Rules of Order]] Newly Revised, 10th edition.''<ref name="autogenerated1">{{cite book|ref=harv|year=2000|pages=411–414|title=Robert's Rules of Order Newly Revised, 10th edition|isbn=978-0738203072|publisher=Da Capo Press|last=Robert|first=Henry}}</ref> as an example of "[[preferential voting]]," a term covering "any of a number of voting methods by which, on a single ballot when there are more than two possible choices, the second or less-preferred choices of voters can be taken into account if no candidate or proposition attains a majority. While it is more complicated than other methods of voting in common use and is not a substitute for the normal procedure of repeated balloting until a majority is obtained, preferential voting is especially useful and fair in an election by mail if it is impractical to take more than one ballot. In such cases it makes possible a more representative result than under a rule that a plurality shall elect...."Preferential voting has many variations. One method is described ... by way of illustration."<ref>{{harvnb|Robert|2000|p=411}}</ref> And then the instant runoff voting method is detailed.<ref>{{harvnb|Robert|2000|pp=412–413}}</ref> |
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''Robert's Rules'' continues: "The system of preferential voting just described should not be used in cases where it is possible to follow the normal procedure of repeated balloting until one candidate or proposition attains a majority. Although this type of preferential ballot is preferable to an election by plurality, it affords less freedom of choice than repeated balloting, because it denies voters the opportunity of basing their second or lesser choices on the results of earlier ballots, and because the candidate or proposition in last place is automatically eliminated and may thus be prevented from becoming a compromise choice."<ref name=roberts414>{{harvnb|Robert|2000|p=414}}</ref> Two other books on parliamentary procedure take a similar stance, disapproving of plurality voting and describing preferential voting as an option, if authorized in the bylaws, when repeated balloting is impractical: [[The Standard Code of Parliamentary Procedure]]<ref>{{cite parl|title=TSC|pages=148|edition=4th}}</ref> and [[Riddick's Rules of Procedure]].<ref>{{cite parl|title=RID|pages=145|edition=1985|year=1985}}</ref> |
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==Global use== |
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{{main|History and use of instant-runoff voting}} |
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{{see also|Table of voting systems by country}} |
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===Australia=== |
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{{see also|Australian electoral system|Electoral systems of the Australian states and territories}} |
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Instant-runoff voting is used for national elections in Australia to elect members of the [[Australian House of Representatives]]. The [[Australian Senate]] uses a modified form, combining it with a [[proportional representation]] system (the [[Single transferable vote]]); candidates are eliminated until the remaining parties can be said to have a sufficient proportion of the vote to earn a seat.<ref name="Australian Electoral Commission"/> |
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===Canada=== |
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IRV is used to elect the leaders of two political parties in Canada, the [[Liberal Party of Canada]]<ref>{{cite web|url=https://www.liberal.ca/newsroom/party-news/liberals-vote-overwhelmingly-in-favour-of-one-member-one-vote-2/ |title=Liberals vote overwhelmingly in favour of one-member, one-vote |publisher=Liberal.ca |date=2009-05-02 |accessdate=2011-04-17}}</ref> and the [[Conservative Party of Canada]]. Canadian Prime Minister [[Stephen Harper]] won an IRV election to become party leader in the [[Conservative Party of Canada leadership election, 2004|2004 leadership election]]. |
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===Fiji=== |
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Instant-runoff voting is used for national elections to elect members of the [[House of Representatives of Fiji]].<ref name="Fiji Constitution, Section 541"/> In Fiji, each voter casts ballots in two elections: one for the minority of seats that are elected by universal suffrage and the remaining in one of the communal constituencies reserved to different ethnic groups. |
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===India=== |
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IRV is used in numerous [[electoral college]] environments, including the election of the [[President of India]] by the members of the [[Parliament of India]] and of the [[Vidhan Sabha]]s – the [[States and territories of India|state]] legislatures.<ref>{{cite web|author=Posted by swapnil |url=http://swapsushias.blogspot.com/2010/10/presidents-of-indiarashtrapati.html |title=IAS OUR DREAM: Presidents of India,Rashtrapati Bhavan,Trivia |publisher=Swapsushias.blogspot.com |date=2010-10-29 |accessdate=2010-12-03}}</ref> |
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===Ireland=== |
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While most [[elections in the Republic of Ireland]] uses the [[single transferable vote]] (STV),<ref>{{cite web|url=http://www.environ.ie/en/LocalGovernment/Voting/PublicationsDocuments/FileDownLoad,1895,en.pdf|title=Guide to Ireland’s PR-STV Electoral System|last=Franchise Section|date=February 2011.|publisher=Department of the Environment, Heritage and Local Government|accessdate=29 April 2011}}</ref> in single-winner contests this reduces to IRV.<ref name="Muckerras">{{cite journal|last=Muckerras|first=Malcolm|coauthors=William Muley|year=1998|title=Preferential Voting in Australia, Ireland and Malta|journal=Griffith Law Review|volume=7|issue=2|pages=225–248|url=http://kirra.austlii.edu.au/au/journals/GriffLawRw/1998/14.pdf}}</ref> This is the case in all [[Irish presidential election|Presidential elections]]<ref name="Muckerras"/> and [[Seanad panel]] by-elections,<ref name="panelact1947">[http://www.irishstatutebook.ie/1947/en/act/pub/0042/sec0058.html Seanad Electoral (Panel Members) Act, 1947 §58: Provision applicable where more than one casual vacancy.] Irish Statute Book</ref> and most [[List of Irish by-elections|Dáil by-election]]s<ref name="Muckerras"/> In the rare event of multiple simultaneous vacancies in a single [[Dáil constituency]], a single STV by-election may be held;<ref>[http://www.irishstatutebook.ie/1992/en/act/pub/0023/sec0039.html Electoral Act, 1992 §39(3)] Irish Statute Book</ref> for Seanad panels, multiple IRV by-elections are held.<ref name="panelact1947"/> |
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===New Zealand=== |
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IRV is used in the elections of city [[mayor]]s in New Zealand.<ref name="Elections - 2007 Final Results"/> |
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===Papua New Guinea=== |
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Since 2003 the national parliament of [[Papua New Guinea]] has been elected using an IRV variant called Limited Preferential Voting, where voters are limited to ranking three candidates.<ref>{{cite web|url=http://archive.fairvote.org/articles/papuanewguinea.htm |title=Center for Voting and Democracy |publisher=Archive.fairvote.org |date= |accessdate=2011-04-17}}</ref><ref>{{cite web|url=http://aceproject.org/ero-en/regions/pacific/PG/Papua_new_guinea_leaflet.pdf/view |title=Limited Preferential Voting |publisher=Aceproject.org |date= |accessdate=2010-10-03}}</ref> |
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===United Kingdom=== |
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In the United Kingdom the system is commonly known as the alternative vote. It is used to elect the leaders of the [[Labour Party (UK)|Labour Party]] and the [[Liberal Democrats]]. (The leader of the [[Conservative Party (UK)|Conservative Party]] is elected under a similar system, a variant of the [[exhaustive ballot]].) It is also used for [[by elections to the House of Lords|by-elections to the British House of Lords]], in which [[hereditary peer]]s are selected for that body.<ref name="Notice of Conservative Hereditary Peers' By-Election to the House of Lords">{{cite web| url = http://www.parliament.uk/documents/lords-information-office/holnotice20100601.pdf |title = Notice of Conservative Hereditary Peers' By-Election to the House of Lords |publisher=House of Lords}}</ref> AV is also used by members of parliament to elect the chairmen of select committees and the [[Speaker of the House of Lords]]. The Speaker of the House of Commons is elected by the exhaustive ballot. |
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In 2010 the Conservative/Liberal Democrat coalition government agreed to hold a [[United Kingdom Alternative Vote referendum, 2011|national referendum on the alternative vote]],<ref>{{cite news|url=http://news.bbc.co.uk/2/hi/uk_news/politics/election_2010/8675848.stm |title=BBC's Q&A: The Conservative-Lib Dem coalition |publisher=BBC |date=2010-05-13 |accessdate=2010-10-03}}</ref> held on 5 May 2011.<ref>{{cite news|author=Norman Smith Chief political correspondent, BBC Radio 4 |url=http://news.bbc.co.uk/1/hi/politics/10483841.stm |title=Voting reform referendum planned for next May |publisher=BBC|date=2010-07-02 |accessdate=2010-10-03}}</ref> The proposal would have affected the way in which [[Members of Parliament]] are elected to the [[House of Commons (United Kingdom)|British House of Commons]] at Westminster. The [[Results of the United Kingdom Alternative Vote referendum, 2011|result of the referendum]] was a vote against adoption of the alternative vote by a margin of 67.9 percent to 32.1 percent.<ref>[http://ukreferendumresults.aboutmyvote.co.uk/en/default.aspx The Electoral Commission] Referendum result</ref> |
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===United States=== |
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{{seealso2|[[Ballot Access News]] for occasional related news in the United States}} |
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IRV is used by several jurisdictions in the United States, including [[San Francisco]]<ref name=mpr20090510/> and [[Oakland, California]],<ref name=or2010/> and [[Minneapolis]] and [[Saint Paul, Minnesota]].<ref name=mpr20090510/> |
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United States private associations that use IRV<ref name="Organizations & Corporations"/> include the [[Hugo Award]]s for science fiction<ref name="Oscars Copy Hugos"/> and the [[Academy of Motion Picture Arts and Sciences]] in selection of the Oscar for Best Picture.<ref name="www.oscars.org"/> |
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==Similar systems== |
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===Runoff voting=== |
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The term ''instant runoff voting'' is derived from the name of a class of voting systems called runoff voting. In runoff voting voters do not rank candidates in order of preference on a single ballot. Instead a similar effect is achieved by using multiple rounds of voting. All multi-round runoff voting systems allow voters to change their preferences in each round, incorporating the results of the prior round to influence their decision. This is not possible in IRV, as participants vote only once, and this prohibits certain forms of [[tactical voting]] that can be prevalent in 'standard' runoff voting. |
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===Exhaustive ballot=== |
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A system closer to IRV is the [[exhaustive ballot]]. In this system—one familiar to fans of the television show [[American Idol]]—one candidate is eliminated after each round, and many rounds of voting are used, rather than just two.<ref>{{cite web|url=http://www.securevote.com.au/gloss_of_terms.html#e |title=Glossary: Exhaustive ballot |publisher=Securevote.com.au |date= |accessdate=6 May 2010}}</ref> Because holding many rounds of voting on separate days is generally expensive, the exhaustive ballot is not used for large scale, public elections. |
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===Two-round systems=== |
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The simplest form of runoff voting is the [[two-round system]], which typically excludes all but two candidates after the first round, rather than gradually eliminating candidates over a series of rounds. Eliminations can occur with or without allowing and applying preference votes to choose the final two candidates. A second round of voting or counting is only necessary if no candidate receives an overall majority of votes. This system is used in France. |
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===Contingent vote (supplementary)=== |
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[[Image:IRV-toptwo flowchart.png|thumb|Top-two IRV]] |
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The [[contingent vote]], also known as '''Top-two IRV''', or ''batch-style'', is the same as IRV except that if no candidate achieves a majority in the first round of counting, all but the two candidates with the most votes are eliminated, and the second preferences for those ballots are counted. As in IRV, there is only one round of voting. |
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Under a variant of contingent voting used in [[Sri Lanka]], and the elections for [[Mayor of London]] in the United Kingdom, voters rank a specified maximum number of candidates. In London, the [[Supplementary Vote]], allows voters to express first and second preferences only. Sri Lankan voters rank up to three candidates for the [[President of Sri Lanka]], in a [[Contingent vote#Sri Lankan contingent vote|variant of the contingent vote]]. |
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While similar to "sequential elimination" IRV, top-two can produce different results. Excluding more than one candidate after the first count might eliminate a candidate who would have won under sequential elimination IRV. Restricting voters to a maximum number of preferences is more likely to exhaust ballots if voters do not anticipate which candidates will finish in the top two. This can encourage voters to vote more [[tactical voting|tactically]], by ranking at least one a candidate they think is likely to win. |
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Conversely, a practical benefit of 'contingent voting' is expediency and confidence in the result with only two rounds. Particularly in elections with few (e.g., fewer than 100) voters, numerous ties can destroy confidence. Heavy use of tie-breaking rules leaves uncomfortable doubts over whether the winner might have changed if a recount was performed. |
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===In a larger runoff process=== |
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IRV may also be part of a larger runoff process: |
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* Some jurisdictions that hold runoff elections allow absentee (only) voters to submit IRV ballots, because the interval between votes is too short for a second round of absentee voting. IRV ballots enable absentee votes to count in the second (general) election round if their first choice does not make the runoff. [[Arkansas]], [[Louisiana]], [[South Carolina]] and [[Springfield, Illinois]] adopt this approach.<ref>{{cite web|url=http://www.electionline.org/Portals/1/Publications/SC.EAP.2006primary.pdf |title=Initiatives – Pew Center on the States |publisher=Electionline.org |date= |accessdate=6 May 2010}}</ref><ref>[http://www.fvap.gov/pubs/vag/pdfvag/la.pdf Louisiana absentee balloting]{{Dead link|date=May 2010}}: ''E. Special Absentee Ballot for General Election: The special ballot permits you to vote in the following general election by writing in numbers according to your choice of preference for each candidate. You put the number one next to the name of the candidate who is your first choice, the number two for your second choice, and so forth so that, in consecutive numerical order, you write a number indicating your preference next to each candidate’s name on the ballot.''</ref> |
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* IRV can quickly eliminate weak candidates in early rounds of an [[exhaustive ballot]] runoff, using rules to leave the desired number of candidates for further balloting. |
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* IRV allows an arbitrary victory threshold in a single round of voting, e.g., 60%. In such cases a second vote may be held to confirm the winner.<ref>For example, in 2006, the [[Independence Party of Minnesota]] used IRV for its endorsement elections, requiring 60% to win, and ''exhaustive balloting'' to follow if needed.</ref> |
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* IRV elections that require a majority of cast ballots but not that voters rank all candidates may require more than a single IRV ballot due to exhausted ballots. |
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* Robert's Rules recommends [[preferential voting]] for elections by mail and requiring a majority of cast votes to elect a winner, giving IRV as their example. For in-person elections, they recommend repeated balloting until one candidate receives an absolute majority of all votes cast. Repeated voting allows voters to turn to a candidate as a compromise who polled poorly in the initial election.<ref name="autogenerated1"/> |
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The common feature of these IRV variations is the one vote is counted per ballot per round, with rules that eliminate the weakest candidate(s) in successive rounds. Most IRV implementations drop the "[[majority]] of cast ballots" requirement.<ref>[http://www.leg.state.vt.us/docs/2004/bills/intro/S-022.HTM Vermont S.22 1(c)3] Sec. 7. (6) ... if neither of the last two remaining candidates in an election ... received a majority, the report and the tabulations performed by the instant runoff count committee shall be forwarded to the Washington superior court, which shall issue a certificate of election to whichever of the two remaining candidates received the greatest number of votes at the conclusion of the instant runoff tabulation, and send a certified copy of the tabulation and results to the secretary of state.</ref> |
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==See also== |
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*[[Alternative Vote Plus (AV+)]] or Alternative Vote Top-up proposed by the [[Jenkins Commission (UK)]] |
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*[[Outline of democracy]] |
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*[[None of the above]] (NOTA) or [[None of the above#Re-open Nominations (RON)|Re-Open Nominations]] (RON) |
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==References== |
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{{Reflist|colwidth=30em}} |
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==External links== |
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* 2010 articles from the [http://www.re-constitution.org.uk/news/articles/37/ Constitution Society] and [http://www.electoral-reform.org.uk/article.php?id=55 Electoral Reform Society] summarizing the proposed change in the United Kingdom to IRV/Alternative Vote |
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;IRV in practice |
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* [http://aceproject.org/ace-en/topics/es/esd/esd01/esd01d/esd01d01 Advantages and disadvantages of AV] from the [http://www.aceproject.org/ ACE Project] Electoral Design Reference Materials |
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* [http://www.idea.int/publications/esd/index.cfm A Handbook of Electoral System Design] from [http://www.idea.int/ International IDEA] |
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* [http://www.aec.gov.au/ Australian Electoral Commission Web Site] |
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* [http://www.australianpolitics.com/elections/features/preferential.shtml Preferential Voting in Australia] from Australian Politics.com |
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* [http://www.sfgov2.org/index.aspx?page=599 San Francisco Department of Elections, California] |
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* [http://www.acgov.org/rov/rcv/ Alameda County Registrar of Voters, California] |
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* [http://www.ci.minneapolis.mn.us/elections/rcv.asp City of Minneapolis, Minnesota] |
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* [http://www.sboe.state.nc.us/content.aspx?id=29 State of North Carolina] |
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;Demos and simulations |
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* [http://www.choiceranker.com/election.php?eid=6 Indaba.org – Demo of an IRV Ballot, including the Visual Display of a Runoff] |
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* [http://news.bbc.co.uk/1/hi/uk_politics/8506306.stm BBC: Would the alternative vote have changed history?, illustration of how the results of the last six general elections might have looked had the 'alternative vote' system been in place.] |
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* [http://www.openstv.org/ OpenSTV – Open source software for computing IRV and STV] |
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* [http://www.demochoice.org/dcballot.php?poll=Futurama1 ''Favourite Futurama Character Poll''] |
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* [http://zesty.ca/voting/sim/ Voting System Visualizations] – 2-dimensional plots of results of various systems, with assumptions of sincere voting behavior. |
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* [http://bolson.org/voting/essay.html Simulation Of Various Voting Models for Close Elections] Opposition article by Brian Olson. |
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;Advocacy groups and positions |
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* [http://www.yestofairervotes.org/ Yes to Fairer Votes ] campaign site for the Yes side of the 2011 UK electoral reform referendum |
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* [http://www.fairvote.org/instant-runoff-voting Instant Runoff Voting] at [[FairVote]] |
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* [http://www.lwvofvt.org/files/position_on_voter_rights_and_government.pdf League of Women Voters of Vermont] |
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* [http://instantrunoff.com/ InstantRunoff.com] |
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* [http://www.123toronto.ca/main.htm Ranked Ballot Initiative of Toronto, Canada] |
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* [http://www.rooseveltcampusnetwork.org/policy/instant-runoff-voting-national-elections Roosevelt Institution] |
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* [http://www.voterchoicema.org/ Citizens for Voter Choice :: Massachusetts] |
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* [http://www.fairvotemn.org/ FairVote Minnesota] |
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* [http://www.commoncause.org/site/pp.asp?c=dkLNK1MQIwG&b=4849119 Common Cause Massachusetts] |
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* [http://www.brookings.edu/papers/2007/0228electionreform_Opp08.aspx/ Brookings Institution's "Empowering Moderate Voters" paper] |
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* [http://blogs.abc.net.au/antonygreen/2011/02/does-the-alternative-vote-bring-tyranny-to-australia.html Does the Alternative Vote Bring Tyranny to Australia? - Antony Green ABC] |
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;Opposition groups and positions |
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* [http://www.av2011.co.uk/ AV 2011] Anti-AV Referendum Site for the 2011 UK electoral reform referendum |
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* [http://www.no2av.org/ No to AV] campaign site for the No side of the 2011 UK electoral reform referendum |
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* [http://www.fairvote.ca/files/AV-backgrounder-august2009_1.pdf Fair Vote Canada paper] on the Alternative Vote |
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* [http://www.rangevoting.org/rangeVirv.html IRV page] at the [[Center for Range Voting]] |
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* [http://www.ncvoter.net/downloads/Instant_Runoff_Voting_Value_and_Risks_Report.pdf Instant Runoff Voting Report] Values and Risks Report by the N.C. Coalition for Verified Voting |
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{{voting systems}} |
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{{United Kingdom Alternative Vote referendum, 2011}} |
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{{DEFAULTSORT:Instant-Runoff Voting}} |
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[[Category:Instant-runoff voting| ]] |
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[[Category:Non-monotonic electoral systems]] |
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[[Category:Preferential electoral systems]] |
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[[Category:Single winner electoral systems]] |
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[[ar:اقتراع تفضيلي]] |
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[[cs:Alternativní hlasování]] |
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[[cy:Pleidlais amgen]] |
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[[de:Instant-Runoff-Voting]] |
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[[es:Votación preferencial]] |
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[[fr:Vote alternatif]] |
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[[ja:Instant-runoff voting]] |
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[[vi:Bầu cử thay thế]] |
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[[zh:排序複選制]] |
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Revision as of 14:20, 7 May 2011
Wikipedia is the worst website in the world. Its editors are extremely rude and they do not get punished for their terrible behavior. User:HXL49 should be blocked from editing wikipedia forever. I hate wikipedia. Sincerely User talk:Ryan Vesey