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68-947: [REDACTED] Look up irv in Wiktionary, the free dictionary. IRV or Irv or variant , may refer to: Instant-runoff voting , a type of ranked preferential voting counting method used in single-seat elections with more than two candidates Irvine railway station , North Ayrshire, Scotland (National Rail station code IRV ) Anton Irv (1886–1919), Estonian soldier Irv (given name) See also [ edit ] [REDACTED] Search for "irv"  or "i-r-v" on Misplaced Pages. All pages with titles beginning with IRV All pages with titles beginning with Irv All pages with titles containing irv Irvin Irvine (disambiguation) Irving (disambiguation) Irve (disambiguation) Topics referred to by

136-688: A center squeeze , which may sometimes prevent the election of a Condorcet winner. Whilst the Marquis de Condorcet early on showed that it did not satisfy his Condorcet winner criterion , which it may fail under certain scenarios, instant-runoff voting satisfies many other majoritarian criteria, such as the majority criterion , mutual majority criterion and the Condorcet loser criterion . Advocates have argued these properties are positive, because voting rules should encourage candidates to focus on their core support or political base, rather than building

204-508: A broad coalition. They also note that in countries like the United Kingdom without primaries or runoff elections , IRV can prevent spoiler effects by eliminating minor-party candidates in early rounds, and that unlike plurality, it is not affected by the presence of duplicate candidates (clones) . In instant-runoff voting, as with other ranked voting rules, each voter orders candidates from first to last. The counting procedure

272-524: A candidate can bring about a less desirable result by unwisely choosing to stand in an election; this is because of the spoiler effect , by which a new candidate can "split the vote" and cost another similar candidate the election. The exhaustive vote's system of multiple rounds makes it less vulnerable to the spoiler effect than the plurality system or the two round system. This is because a potential spoiler candidate often has only minor support; therefore he will be eliminated early and his supporters will have

340-433: A candidate reaches a majority. (In some circumstances, the two or more lowest candidates can be eliminated simultaneously if together they have fewer votes than the lowest candidate above them. In other words, this "bulk exclusion" cannot change the order of elimination, unlike a two-round system.) Because voters may have to cast votes several times, the exhaustive ballot is not used in large-scale public elections. Instead it

408-593: A candidate who nevertheless remains more preferred by voters. For example, in the 2009 Burlington, Vermont, mayoral election , if the Republican candidate who lost in the final instant runoff had not run, the Democratic candidate would have defeated the winning Progressive candidate. In that sense, the Republican candidate was a spoiler—albeit for an opposing Democrat, rather than some political ally—even though leading in first choice support. This also occurred in

476-402: A candidate who would otherwise have stood. The exhaustive ballot is vulnerable to strategic nomination for the same reasons that it is open to the voting tactic of "compromising". This is because a candidate who knows they are unlikely to win can bring about the election of a more desirable compromise candidate by withdrawing from the race, or by never standing in the first place. By the same token

544-480: A class of instant runoff- Condorcet hybrids. IRV is also completely immune to the burying strategy: ranking a strong opposition candidate lower can't get one's preferred candidate elected. Tactical voting in IRV seeks to alter the order of eliminations in early rounds, to ensure that the original winner is challenged by a stronger opponent in the final round. For example, in a three-party election where voters for both

612-419: A convention or caucus. In some respects the exhaustive ballot closely resembles instant-runoff voting (also known as the "Alternative Vote"). Under both systems if no candidate has an absolute majority in the first round then there are further rounds, with the candidate with the fewest votes being eliminated after each round. However while under the exhaustive ballot each round involves voters returning to cast

680-411: A majority of votes. Two other books on American parliamentary procedure, The Standard Code of Parliamentary Procedure and Riddick's Rules of Procedure , take a similar stance. The term instant-runoff voting is derived from the name of a class of voting methods called runoff voting. In runoff voting voters do not rank candidates in order of preference on a single ballot. Instead a similar effect

748-616: A majority. Compared to a plurality voting system that rewards only the top vote-getter, instant-runoff voting mitigates the problem of wasted votes . However, it does not ensure the election of a Condorcet winner , which is the candidate who would win a direct election against any other candidate in the race. All forms of ranked-choice voting reduce to plurality when all ballots rank only one candidate. By extension, ballots for which all candidates ranked are eliminated are equivalent to votes for any non-winner in plurality, and considered exhausted ballots . Some political scientists have found

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816-415: 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 marginal candidate will not result in the marginal candidate's election. An IRV method reduces this problem, since the voter can rank the marginal candidate first and the mainstream candidate second; in

884-415: A new vote, under instant-runoff, voters vote only once. This is possible because, rather than voting for only a single candidate, the voter ranks all of the candidates in order of preference. These preferences are then used to "transfer" the votes of those whose first preference has been eliminated during the course of the count. Because the exhaustive ballot involves separate rounds of voting, voters can use

952-747: A result of American influence, the term ranked-choice voting is often used in Canada as well. American NGO FairVote has promoted the terminology "ranked-choice voting" to refer to IRV, a choice that has caused controversy and accusations that the organization is attempting to obscure the existence of other ranked-choice methods that could compete with IRV. IRV is occasionally referred to as Hare's method (after Thomas Hare ) to differentiate it from other ranked-choice voting methods such as majority-choice voting , Borda , and Bucklin , which use weighted preferences or methods that allow voter's lower preference to be used against voter's most-preferred choice. When

1020-422: Is a single-winner , multi-round elimination rule that uses ranked voting to simulate a series of runoffs with only one vote. In each round, the candidate with the fewest votes is eliminated, and their votes are transferred to their next available preference until one of the options reaches a majority of the remaining votes. Instant runoff falls under the plurality-with-elimination family of voting methods, and

1088-424: Is a voting system used to elect a single winner. Under the exhaustive ballot the elector casts a single vote for his or her chosen candidate. However, if no candidate is supported by an overall majority of votes then the candidate with the fewest votes is eliminated and a further round of voting occurs. This process is repeated for as many rounds as necessary until one candidate has a majority. The exhaustive ballot

1156-540: Is achieved by using multiple rounds of voting. All multi-round runoff voting methods allow voters to change their preferences in each round, incorporating the results of the prior round to influence their decision, which is not possible in IRV. The runoff method closest to IRV is the exhaustive ballot . In this method—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. Because holding many rounds of voting on separate days

1224-501: Is described in Robert's Rules of Order Newly Revised as an example of ranked-choice voting that can be used to elect officers. Robert's Rules note that ranked-choice systems (including IRV) are an improvement on simple plurality but recommend against runoff-based rules because they often prevent the emergence of a consensus candidate with broad support. The book instead recommends repeated balloting until some candidate manages to win

1292-595: Is different from Wikidata All article disambiguation pages All disambiguation pages Instant-runoff voting Condorcet methods Positional voting Cardinal voting Quota-remainder methods Approval-based committees Fractional social choice Semi-proportional representation By ballot type Pathological response Strategic voting Paradoxes of majority rule Positive results Instant-runoff voting ( IRV ) ( US : ranked-choice voting or RCV , AU : preferential voting , UK : alternative vote )

1360-450: Is generally expensive, the exhaustive ballot is not used for large-scale, public elections. A more practical form of runoff voting is the two-round system , which excludes all but the top-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

1428-411: Is impossible under IRV. In IRV the electorate votes only once, so candidates must make the judgement of whether or not to participate in an election before the poll, and before even one round of counting has occurred. The exhaustive ballot encourages candidates to appeal to a broad cross-section of voters. This is because, in order to eventually receive an absolute majority of votes, it is necessary for

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1496-559: Is only necessary if no candidate receives an overall majority of votes. This method is used in Mali, France and the Finnish and Slovenian presidential election. The contingent vote , also known as "top-two IRV", 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

1564-873: Is only one round of voting. Under a variant of contingent voting used in Sri Lanka , and formerly for the elections for Mayor of London in the United Kingdom, voters rank a specified maximum number of candidates. In London, the supplementary vote allowed voters to express first and second preferences only. Sri Lankan voters rank up to three candidates to elect the president of Sri Lanka . Exhaustive ballot Positional voting Cardinal voting Quota-remainder methods Approval-based committees Fractional social choice Semi-proportional representation By ballot type Pathological response Strategic voting Paradoxes of majority rule Positive results The exhaustive ballot

1632-423: Is similar to the two-round system but with key differences. Under the two round system if no candidate wins a majority on the first round, only the top two recipients of votes advance to the second (and final) round of voting, and a majority winner is determined in the second round. By contrast, on the exhaustive ballot only one candidate is eliminated per round; thus, several rounds of voting may be required until

1700-417: Is the winner. As noted above the exhaustive ballot is similar to the two-round system . However under the two-round system if no candidate achieves an absolute majority in the first round then, rather than just a single candidate being eliminated, all candidates are immediately excluded except the two with the most votes. There is then a second and final round. Because, at most, it requires voters to return to

1768-423: Is then as follows: It is possible for a candidate to win an instant-runoff race without any support from more than half of voters, even when there is an alternative majority-approved candidate; this occurs when some voters truncate their ballots to show they do not support any candidates in the final round. In practice, candidates who do not receive a majority of votes in the first round usually do not finish with

1836-427: Is this weak candidate, rather than a stronger rival, who remains to challenge a voter's preferred candidate in later rounds. By supporting a "push over" candidate it is hoped to eliminate a stronger candidate who might have gone on to win the election. The "push over" tactic requires voters to be able to reliably predict how others will vote. It runs the risk of backfiring, because if the tactical voter miscalculates then

1904-687: Is thus closely related to rules like the exhaustive ballot and two-round runoff system . IRV has found some use in national elections in several countries , predominantly in the Anglosphere . It is used to elect members of the Australian House of Representatives and the National Parliament of Papua New Guinea as well as the President of India , the President of Ireland , and the President of Sri Lanka . The rule

1972-657: Is usually used in elections involving, at most, a few hundred voters, such as the election of a prime minister or the presiding officer of an assembly. The exhaustive ballot is currently used, in different forms, to elect the members of the Swiss Federal Council , the First Minister of Scotland , the President of the European Parliament , and the speakers of the House of Commons of Canada ,

2040-477: The 1972 election had the largest number of winners who would not have won under first past the post but still only 14 out of 125 seats filled were not won by the first-count leader. The effect of IRV on voter turnout is difficult to assess. In a 2021 report, researchers at New America , a think tank based in Washington, D. C., said it may increase turnout by attracting more and more diverse candidates, but

2108-400: The 2022 Alaska's at-large congressional district special election . If Republican Sarah Palin , who lost in the final instant runoff, had not run, the more centrist Republican candidate, Nick Begich, would have defeated the winning Democratic candidate, Mary Peltola . The system has had a mixed reception among political scientists and social choice theorists . Some have suggested that

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2176-869: The British House of Commons and the Scottish Parliament , the host city of the Olympic Games and the host of the FIFA World Cup , and, formerly, to elect the President and the State Comptroller of Israel , which are now elected—though still indirectly by the Knesset —using a two-round system . In each round of an exhaustive ballot the voter simply marks an 'x' beside his or her favourite candidate. If no candidate has an absolute majority of votes (i.e., more than half) in

2244-457: The left and right prefer the centrist candidate to stop the opposing candidate from winning, those voters who care more about defeating the opposition than electing their own candidate may cast a tactical first-preference vote for the centrist candidate. Proponents of IRV claim that IRV eliminates the spoiler effect, since IRV makes it safe to vote honestly for marginal parties. Under a plurality method, voters who sympathize most strongly with

2312-572: The single transferable vote (STV) method is applied to a single-winner election, it becomes IRV; the government of Ireland has called IRV "proportional representation" based on the fact that the same ballot form is used to elect its president by IRV and parliamentary seats by proportional representation (STV), but IRV is a non-proportional winner-take-all (single-winner) election method, while STV elects multiple winners. State law in South Carolina and Arkansas use "instant runoff" to describe

2380-480: The "alternative vote" (AV). Australians, who use IRV for most single winner elections, call IRV "preferential voting". While this term is widely used by Australians, it is somewhat of a misnomer . Depending on how "preferential" is defined, the term would include all voting systems, apply to any system that uses ranked ballots (thus both IRV and STV), or would exclude IRV (IRV fails positive responsiveness because ballot markings are not interpreted as "preferences" in

2448-441: The 2018 primary elections, that IRV would result in "one person, five votes", as opposed to " one person, one vote ". Federal judge Lance Walker rejected these claims, and the 1st circuit court denied Poliquin's emergency appeal. Often instant-runoff voting elections are won by the candidate who leads in first-count vote tallies so they choose the same winner as first-past-the-post voting would have. In Australia federal elections,

2516-490: The Condorcet winner to the IRV winner have an incentive to use the compromising strategy. IRV is also sometimes vulnerable to a paradoxical strategy of ranking a candidate higher to make them lose, due to IRV failing the monotonicity criterion . Research suggests that IRV is very resistant to tactical voting. In a test of multiple methods, instant runoff was found to be the second-most-resistant to tactical voting, after

2584-412: The candidate intended as a "push over " might end up actually beating the voter's preferred candidate. Instant-runoff voting is less susceptible to this tactic, as voters cannot change their first preference in successive rounds. Once a voter has chosen a push over as their preferred candidate, it will remain so until this candidate is eliminated, increasing the likelihood of the push over getting elected at

2652-488: The capital to be as close to them as possible. The options are: The preferences of each region's voters are: Round 1. In the first round of voting everybody votes for their own city: Round 2. No candidate has a majority in the first round, so Chattanooga (with the fewest votes) is eliminated and the remaining three candidates proceed to Round 2. In this round the Chattanooga supporters vote instead for Knoxville,

2720-402: The election had they survived a little longer. This can create strong incentives for voters to vote tactically. The exhaustive ballot is also vulnerable to the tactic of "push over", where voters vote tactically for an unpopular "push over" candidate in one round as a way of helping their true favourite candidate win in a later round. The purpose of voting for the "push over" is to ensure that it

2788-413: The election of Fruit. These six voters can do this by voting for Ice Cream in the first round as a "push over". If they do this then the votes cast in the first round will look like this: This time Apple Pie is eliminated in the first round and Ice Cream and Fruit survive to the second round. This outcome is deliberate. The tactical voters know that Ice Cream will be an easier candidate for Fruit to beat in

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2856-463: The expense of the preferred candidate. In the example above Knoxville wins, the last choice of both Nashville and Memphis supporters. If Memphis supporters had compromised by voting for Nashville (their second choice) in the first round then Nashville would have been elected immediately, while if Nashville supporters had all compromised by voting for their second choice of Chattanooga in the first round, then Chattanooga would have gone on to be elected in

2924-428: The first place. Spatial model simulations indicate that instant runoff rewards strategic withdrawal by candidates. Gibbard's theorem demonstrates that no (deterministic, non-dictatorial) voting method can be entirely immune from tactical voting. This implies that IRV is susceptible to tactical voting in some circumstances. In particular, when there exists a Condorcet winner who IRV fails to elect, voters who prefer

2992-464: The first round, then the candidate with the fewest votes is eliminated while all other candidates advance to a second round. If there is still no candidate with a majority then the candidate with the fewest votes is again eliminated and there is a third round. The process repeats itself for as many rounds as are necessary for one candidate to achieve a majority. If necessary, the election will continue until only two candidates remain. When this occurs one of

3060-566: The form of the single transferable vote . Henry Richmond Droop then proposed applying the system to single-winner contests. (He also invented the Droop quota , which equates to a simple majority in a single-winner contest.) Nonpartisan primary system with IRV in the second round (among top four candidates) in Alaska. In the United States, the sequential elimination method used by IRV

3128-656: The impact would be realized most significantly by getting rid of the need for primaries. The overall impact on diversity of candidates is difficult to detect. Instant-runoff voting derives its name from the way the ballot count simulates a series of runoffs, similar to an exhaustive ballot system , except that voters do not need to turn out several times to vote. It is also known as the alternative vote, transferable vote, ranked-choice voting (RCV), single-seat ranked-choice voting, or preferential voting (but use of some of those terms may lead to misunderstanding as they also apply to STV.) Britons and New Zealanders generally call IRV

3196-477: The likely event that the fringe candidate is eliminated, the vote is not wasted but is transferred to the second preference. However, when the third-party candidate is more competitive, they can still act as a spoiler under IRV, by taking away first-choice votes from the more mainstream candidate until that candidate is eliminated, and then that candidate's second-choice votes helping a more-disliked candidate to win. In these scenarios, it would have been better for

3264-418: The next-closest city to their own. None of the other voters need to change their votes. The results are therefore: Round 3. Nashville is now eliminated, so that only two candidates remain for the final round. The Nashville supporters change their vote to Knoxville, the next nearest city to their own. The result of the third round is therefore: Result: After round three Knoxville has an absolute majority so

3332-497: The opportunity to influence the result of the election by voting for more popular candidates in later rounds. Voters can also counteract the effect of vote splitting by using the "compromise" tactic. The exhaustive vote is essentially vulnerable to the same forms of strategic nomination as instant-runoff voting, the difference being that under the exhaustive vote candidates can use the results of early rounds to inform whether or not they should strategically withdraw in later rounds. This

3400-413: The outcome of the election by voting for more popular candidates once her favourite has been eliminated. However the exhaustive ballot is still vulnerable to tactical voting under some circumstances. Because of the similarity between the two systems it is open to the same forms of tactical voting as instant-runoff voting, as described below. Although the exhaustive ballot is designed to avoid "compromising"

3468-424: The plurality system, which involves only one round, voters are encouraged to vote tactically by voting for only one of the two leading candidates, because a vote for any other candidate will not affect the result. Under the exhaustive ballot this tactic, known as "compromising", is sometimes unnecessary because, even if the voter's first choice is unlikely to be elected, she will still have the opportunity to influence

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3536-444: The polls only once, the two-round system is considered more practical for large public elections than the exhaustive ballot, and is used in many countries for the election of presidents and legislative bodies. However the two systems often produce different winners. This is because, under the two-round system, a candidate may be eliminated in the first round who would have gone on to win the contest if they had been permitted to survive to

3604-476: The practice of having certain categories of absentee voters cast ranked-choice ballots before the first round of an election and counting those ballots in any subsequent runoff elections. This method was first discussed by the Marquis de Condorcet in 1788, who quickly rejected it after showing it would often eliminate a candidate preferred by a majority of voters. IRV was later independently reinvented by Thomas Hare (of England) and Carl Andrae (of Denmark) in

3672-457: The results of one round to inform how they will vote in the next, whereas this is not possible under IRV. Furthermore, because it is necessary to vote only once, instant-runoff voting has been used for large-scale elections in many places. Like instant-runoff voting, the exhaustive ballot is intended to improve upon the simpler " first-past-the-post " (plurality) system by reducing the potential for tactical voting by avoiding "wasted" votes. Under

3740-403: The same term [REDACTED] This disambiguation page lists articles associated with the title IRV . If an internal link led you here, you may wish to change the link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=IRV&oldid=1122102592 " Category : Disambiguation pages Hidden categories: Short description

3808-542: The same) between parties are common. Parties and candidates often encourage their supporters to participate in these preference deals using How-to-vote cards explaining how to use their lower rankings to maximize the chances of their ballot helping to elect someone in the preference deal before it may exhaust. Instant runoff may be manipulable via strategic candidate entry and exit, reducing similar candidates' chances of winning. Such manipulation does not need to be intentional, instead acting to deter candidates from running in

3876-500: The second round than Apple Pie—in other words, that Ice Cream will be a "push-over". In the second round the tactical voters vote for their real first preference, Fruit. Therefore, even if only six Apple Pie supporters prefer Fruit to Ice Cream, the result of the second round will be: Fruit will therefore be elected. The success of this tactic relies on the Fruit supporters being able to predict that Ice Cream can be beaten by Fruit in

3944-436: The second round. Imagine an election in which there are 100 voters who vote as follows: No candidate has an absolute majority of votes so Ice Cream is eliminated in the first round. Ice Cream supporters prefer Apple Pie to Fruit so in the second round they vote for Apple Pie and Apple Pie is the winner. However, if only six Fruit supporters had used the tactic of "push over" then they could have changed this outcome and ensured

4012-437: The second round. If a large majority of Apple Pie supporters had voted for Ice Cream then the "push over" tactic would have backfired, leading to the election of Ice Cream, which Fruit partisans like even less than Apple Pie. The exhaustive ballot can also be influenced by strategic nomination ; this is where candidates and political factions influence the result of an election by either nominating extra candidates or withdrawing

4080-473: The second round. In the example above, the two round system would have selected Nashville instead of Knoxville. A nonpartisan primary election system is a variation of the two-round system which holds a pre-election, and allows the top two candidates to pass to the general election. It generally differs from the two-round system in two ways: (1) the first election is not allowed to pick a winner, and (2) political parties are not allowed to limit their field using

4148-458: The system contributes to higher rates of spoiled votes , partly because the ballot marking is more complex. Most jurisdictions with IRV do not require complete rankings and may use columns to indicate preference instead of numbers. In American elections with IRV, more than 99 percent of voters typically cast a valid ballot. A 2015 study of four local US elections that used IRV found that inactive ballots occurred often enough in each of them that

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4216-420: The system does not do much to decrease the impact of wasted votes relative to plurality. Research has found IRV causes lower confidence in elections and does not substantially affect minority representation, voter turnout , or long-run electoral competition . Opponents have also noted a high rate of repeals for the system. Governor Paul LePage and Representative Bruce Poliquin claimed, ahead of

4284-413: The tactic is still effective in some elections. Compromising is where a voter votes for a certain candidate, not because they necessarily support them, but as a way of avoiding the election of a candidate whom they dislike even more. The compromising tactic is sometimes effective because the exhaustive ballot eliminates candidates who are unpopular in early rounds, who might have had sufficient support to win

4352-412: The third party voters if their candidate had not run at all (spoiler effect), or if they had voted dishonestly, ranking their favourite second rather than first (favorite betrayal). This is the same bracketing effect exploited by Robinette and Tideman in their research on strategic campaigning, where a candidate alters their campaign to cause a change in voter honest choice, resulting in the elimination of

4420-492: The traditional sense. Under IRV (and STV), secondary preferences are used as back-up preferences/contingency votes). Jurisdictions in the United States such as San Francisco , Minneapolis , Maine , and Alaska have tended to use the term "ranked-choice voting" in their laws that apply to IRV contests. The San Francisco Department of Elections claimed the word "instant" in the term "instant-runoff voting" could confuse voters into expecting results to be immediately available. As

4488-454: The two must achieve an absolute majority provided there are an odd number of valid votes cast. Between rounds, the voter is entirely free to change their preferred candidate for whatever reason, even if their preferred candidate has not yet been eliminated from voting. [REDACTED] Suppose that Tennessee is holding an election on the location of its capital . The population is concentrated around four major cities. All voters want

4556-435: The winner of each election did not receive a majority of votes cast in the first round. The rate of inactive ballots in each election ranged from a low of 9.6 percent to a high of 27.1 percent. Instant-runoff voting has notably high resistance to tactical voting but less to strategic nomination . In Australia, preference deals (where one party's voters agree to place another party's voters second, in return for their doing

4624-458: Was first developed and studied by the Marquis de Condorcet , who came to reject it after discovering it could eliminate the majority-preferred candidate in a race (today often called a Condorcet winner ). IRV is known to exhibit other mathematical pathologies , which include non-monotonicity and the no-show paradox . Like some other commonly-used systems, IRV also exhibits a kind of independence of irrelevant alternative violation called

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