Instant-runoff voting

Example Instant runoff voting ballot

Instant runoff voting (IRV), also known as the Alternative Vote (AV), is a form of preferential voting (ranked choice voting). Under the IRV voting system voters rank candidates in order of preference, most commonly in single-winner elections. If no candidate is the first preference of a majority of voters, the candidate with the fewest number of first preference rankings is eliminated and that candidate's ballots are redistributed at full value to the remaining candidates according to the next preference on each ballot. This process is repeated until one candidate obtains a majority of votes among the remaining candidates.

The term instant runoff is used because the method is said to simulate a series of runoff elections tallied in rounds, as in an exhaustive ballot election.^[1] It achieves a similar effect to runoff voting without the time and expense of multiple voting rounds. The result can be found 'instantly' rather than after several separate votes often separated by weeks or months. IRV can also be considered a special case of single transferable vote (STV) when filling a single position.

The historical record offers multiple examples in which IRV counting rules produced a different outcome than the "first past the post" (single seat plurality) system.

[edit] Variations

Adopters of IRV have adjusted the approach in a variety of ways:

• Changing the number of candidates eliminated in each round to be greater than 1
• Holding a second (runoff) election in addition to one or more recounts/reallocations
• Limiting/mandating the number of candidates that each ballot must rank to be considered valid
• Restricting preference ballots to specific classes of voters, such as absentees

[edit] History

Instant runoff voting was invented in 1871 by American architect William Robert Ware.^[2] He evidently based IRV on the single-winner outcome of the single transferable vote, originally developed by Carl Andrae and Thomas Hare.

[edit] Terminology

In the United States, instant runoff voting is an umbrella term associated with ranked choice elections where multiple rounds of counting determine majority winners, low vote-getters 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,^[1] except voters may not change their preferences between rounds.

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 runoff voting, but others use "ranked choice voting" because of the ballot type. It is sometimes referred to as the Alternative Vote (its oldest name) in the United Kingdom and the preferential ballot or preferential voting in Canada and Australia. It has occasionally been referred to as Ware's method, after a U.S. proponent, William Robert Ware.

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.^[3] 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.^[4] State law in South Carolina^[5] and Arkansas^[6] 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.

When the single transferable vote system is applied to a single-winner election it becomes IRV. For this reason IRV is sometimes considered to be merely a special form of STV. However, because STV was designed for multi-seat constituencies, many scholars consider it to be separate from IRV. This article follows that convention. IRV is usually known simply as "STV" in New Zealand and Ireland, although the term Alternative Vote is also used in those countries.

Multiseat variations, such as single transferable vote, have sometimes been labeled as IRV although they should be more accurately called preferential bloc voting, since in bloc voting, multiple votes are counted per ballot at the same time.

An "exhausted ballot" is one in which the voter did not rank all candidates (possibly because the ballot does not permit a complete ranking.) Actual exhaustion occurs only if there are more recounts than the ballot has preferences and all of the ranked candidates are eliminated. At that point, the ballot ceases to affect the outcome, as though it had never been cast.

[edit] Election procedure

Optical scan IRV ballot

In instant runoff voting, as with other ranked election methods, each voter ranks the list of candidates in order of preference. Under a common 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.

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.

Flowchart for counting IRV votes

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, tie-breaking rules determine which candidate to eliminate. Some jurisdictions eliminate all low-ranking candidate simultaneously whose combined number of votes is fewer than the number of votes received by the lowest remaining candidates.

The second preferences of ballots assigned to eliminated candidates are recounted and assigned to one of the remaining candidates, potentially producing a different candidate ordering. The process then repeats until one candidate achieves a majority. Ballots that 'exhaust' all their preferences (all its ranked candidates are eliminated) is discarded.

[edit] Government and non-governmental adopters

Instant runoff voting is used to elect members of the Australian House of Representatives,^[7] the President of Ireland,^[8] the national parliament of Papua New Guinea, and the Fijian House of Representatives.^[9] IRV is employed by several jurisdictions in the United States, including San Francisco and Oakland in California and Minneapolis and St. Paul in Minnesota.^[10] It is used to elect the leaders of the Labour Party and the Liberal Democrats in the United Kingdom and the leader of the Liberal Party of Canada in a national primary^[11] and in the elections of city mayors in a number of countries including the United Kingdom (in the variant known as Supplementary vote)^[12] and New Zealand.^[13]

Many private associations also use IRV,^[14] including the Hugo Awards for science fiction^[15] and the Academy of Motion Picture Arts and Sciences in selection of best picture.^[16]

[edit] Examples

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.^[17]

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.

The result of the 1990 Irish Presidential election provides a good example of how instant runoff voting can produce a different result than the first past the post system. The three candidates were Brian Lenihan of the traditionally dominant Fianna Fáil party, Austin Currie of the nation's second largest party, Fine Gael, and Mary Robinson of the Labour Party and 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 over 80% of Currie's votes, thereby overtaking Lenihan.^{[citation needed]}

[edit] Ballots

As seen above, voters in an IRV election rank candidates on a 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.

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 allows ballot exhaustion.

Some IRV systems consider ballots that do not contain a complete ordering of all candidates to be spoilt. In Australia this variant is known as 'full preferential voting'.^[18] 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.

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.

[edit] Party strategies

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. However this relies on the fact that supporters of a minor party will preference another party based on the advice that they have been given.

[edit] Counting logistics

A hand count is possible under IRV. Several jurisdictions count ballots by hand. Cary, North Carolina's pilot program in October 2007 adopted this approach.^[19] After counting first choices on optical scan equipment at the polls hand-counting covers second and subsequent preference rounds, and is used in most non-U.S. jurisdictions. It is more time-consuming than a plurality count, and may need to occur over a number of rounds.

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.

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.

[edit] Winner-take-all single-seat elections vs. legislative elections

The intention of IRV is to find one candidate acceptable to a majority of voters. It is intended as an improvement on the 'First Past the Post' (plurality) voting system. Under 'First Past the Post' the candidate with the most votes wins, even if they have less than a majority of votes. Election rules may require a runoff election under that condition.

IRV is most suited to elections in which there can be only one winner, such as a mayor or governor. Legislative bodies, city councils or boards also often elect winners by dividing voters into geographic districts, which produce a single winner per race.

Australia is the only nation with a long record of using IRV for the election of legislative bodies. IRV produces representation very similar to that produced by plurality systems, with a result similar to a two party system in parliament like those found in many countries that use plurality and two-round systems. A significant difference is that a smaller third party, such as the National Party of Australia, can co-exist with its coalition partner the Liberal Party of Australia, and can compete against it without fear of losing seats to other parties due to vote splitting.^[20] In the November 2007 elections, at least four candidates ran in every constituency, with an average of seven, but every constituency was won with an absolute majority of votes.^[21]

IRV does not produce proportional representation (PR) for multi-winner elections. It is likely to lead to a smaller number of larger parties in an assembly, rather than a proliferation of small parties. Under a parliamentary system it is more likely to produce single party governments than are PR systems, which tend to produce coalition governments. While IRV is designed to ensure that each individual candidate elected is supported by a majority of those in his or her constituency, if used to elect an assembly it does not ensure this result on a national government level. As in other non-PR systems the party or coalition that wins a majority of seats will sometimes not have the support of an overall majority of voters across the nation.

Many election reformers do not advocate IRV for legislative bodies or city councils that are intended to represent both majorities and minorities (in appropriate proportions).^[22] As with any winner-take-all election method, IRV shut out minority representation. Gerrymandering of single seat districts can also result in minorities gaining majority control of a legislative body, with IRV or any other winner-take-all election method.

According to a 2007 Brookings Institution paper examining voting behavior in the United States, IRV can empower moderate voters. This effect would result from eliminating the primary increasing participation rates by moderates than in the general election.^[23] However, empirical evidence suggests that IRV does not always favor moderates. A 2006 study found that "Fiji's objective of ameliorating ethnic divisions by the adoption of [IRV] was not successful"; the moderate parties would have fared better under PR.^[24]

[edit] Compared to plurality or two-round runoff voting

[edit] Theoretical criteria

Scholars rate voting systems using mathematically-derived voting system criteria Underlying these criteria are Arrow's Theorem and the Gibbard-Satterthwaite theorem, which presume that voters rank all candidates in a strict preference order, among other assumptions. Critics assert that these assumptions are unrealist and invalidate analyses based on them. No ranked preference method can satisfy all of the following criteria, because some are mutually exclusive.

• IRV passes these: majority, later-no-harm, mutual majority, resolvability, Condorcet loser, and, if the right tie-breaker method is used, independence of clones.
• IRV fails these: monotonicity, consistency, Condorcet, participation, reversal symmetry, and independence of irrelevant alternatives.^[25]

[edit] Arguments presented for instant runoff voting

[edit] Reduction of the spoiler effect and tactical voting

Instant runoff voting reduces incentive for insincere voting by reducing the spoiler effect in cases where there are two major candidates and one or more minor candidates.^[26][27] Under "first past the post", voters may have an incentive to vote insincerely for one of the two major candidates, instead of their true favorite, because a vote for the favorite is likely to be "wasted."^[28]

[edit] Number of voting rounds

Robert's Rules of Order calls preferential voting "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 that under a rule that a plurality shall elect. . . . Preferential voting has many variations." The single transferable vote technique used by IRV is the example given.^[29]

Unlike plurality voting, IRV produces a majority winner in every case except an exact tie.

[edit] Measure of voter sentiment

Although this type of preferential ballot better reflects voter sentiment than multi-round plurality voting, it denies voters the opportunity to base subsequent choices on the results of earlier ballots.

However, if there are exhausted ballots, the ultimate majority may still only be a plurality with respect to valid ballots cast in the election.

There are two sources of this incomplete ranking:

1. Some implementations don't allow complete ranking, either due to voting machine limitations or other reasons; for example, San Francisco allows three ranks, even with over twenty candidates.^[30][31]
2. Some voters choose not to rank one or more candidates.^[32] While exhausted votes may leave the winner short of an absolute majority of votes cast, it's also true that many eligible voters choose to rank no candidates, by not voting at all, "exhausting" their "ballots" before even the first round of counting.

To avoid exhaustion, Australia generally requires that voters rank all candidates, considering ballots that do not rank all candidates as spoiled and invalid. 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."^[33]

[edit] Costs

Because it does not require two separate votes, IRV costs less than two-round primary/general or general/runoff election systems.^[34]

[edit] The "spoiler" effect

In plurality elections with three or more candidates, it is possible for every candidate to earn a minority of the vote. When that happens, the candidate or party earning the second-largest minority of the vote sometimes labels the election "spoiled", the rationale being that the votes actually earned by the third-place candidate would have been cast for the second-place candidate, if only lesser candidates were prohibited from participating in elections.

IRV eliminates the spoiler effect in many cases. Under IRV, voters are not forced into choosing between the lesser of two evils and are able to cast runoff (second-choice) votes for as many candidates as they find acceptable.IRV never leaves a "spoiler" candidate for the second-place candidate to blame.

Using ranked preference ballots, any number of candidates can run without "spoiling" being a factor. 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. Every seat was won with a majority of the vote, including several where results would have been different under plurality voting.^[35]

IRV avoided the spoiler effect in the mayoral election in Ann Arbor, Michigan. Albert Wheeler, the city's first African-American mayor, a Democrat, won after trailing the Republican incumbent 49% to 40% in the first round of counting, with remaining votes cast for the Human Rights Party.^[36]

Other single-winner voting systems also reduce or eliminate the spoiler effect.

[edit] Range of choices

Like the two-round system, IRV tends to give voters a wider range of choice among candidates than plurality. More independent and third party candidates are likely to run because the spoiler problems are less severe.^[37] The sequential method of IRV accommodates choices differently than runoff voting by not immediately reducing the field to two in the second round, as typically done in runoff elections.

[edit] Negative campaigning

John Russo, Oakland City Attorney, argued in the [Oakland Tribune, July 24, 2006] that "Instant runoff voting is an antidote to the disease of negative campaigning. 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.^[38][39]

No formal studies have been conducted in the United States. Internationally, Benjamin Reilly suggests instant runoff voting eases ethnic conflict in divided societies.^[40] This feature was a leading argument for why Papua New Guinea adopted instant runoff voting.^[41]

However, critics allege there is a lack of evidence that such an effect occurs as often as suggested.^[42]

[edit] Arguments presented against instant runoff voting

[edit] Similarity to Single Member District Plurality system

Writing in the Canadian Journal of Political Science, Harold J. Jansen studied the Alternative Vote in Canada, concluding that "On balance, it differed little from the single member plurality system."^[43]

[edit] One person one vote

In Ann Arbor, Michigan arguments over IRV in letters to newspapers included "Gives minority candidate voters two votes".^[44] In Stephenson vs. the Ann Arbor Board of City Canvassers in 1975, a Michigan court held Majority Preferential Voting (or M.P.V., as IRV was known) in compliance with the constitution. In his decision, Judge James Fleming wrote:

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.^[45]

[edit] Costs

Pierce County, Washington election officials outlined costs of $3,291,340 to implement IRV for its elections in 2008, covering software and equipment, voter education, testing, staff time, consultants and ballot printing and postage costs. All ballots cast at the precinct had to be counted by central scanners, requiring staff time to check in, visually scan and tabulate ballots.^[46] In 2009 the auditor [chief elections director of Washington counties] reported ongoing costs that are not always balanced by the costs of eliminating runoffs for most county offices, as those elections may be needed for other offices not elected by IRV.^[47]

[edit] Risk of computer fraud

IRV's more complex ballot counting process may lead to more automated vote counting, and potentially more fraud.^[48] IRV supporters attempt to answer these claims with recommended audit procedures.^[49]

[edit] Compared to other reform alternatives

IRV is in use in multiple countries in national, local, party, and non-governmental elections. Recent US Republican and Democratic presidential candidates Barack Obama, Howard Dean, John McCain and Dennis Kucinich support IRV.^[50]

[edit] Minority representation

Majority voting, whether or not it leverages IRV, leaves many voters with a "representative" they oppose. The alternative of proportional representation voting methods enables most or all voters to elect representatives they support.^[51]

[edit] The Condorcet criterion

Failing the Condorcet criterion, like failing the monotonicity criterion, is also related to the resistance IRV and contingent voting have to strategic and tactical voting, by eliminating the possibility of the "burying" strategy.^{[citation needed]} IRV can eliminate, and thus fail to select as winner, a Condorcet winner, i.e. a candidate preferred by a majority to each other candidate in the field (including the eventual winner under IRV). For example, in a three-candidate field suppose that 40% of voters have the ranking XYZ, another 40% have the reverse ZYX, and the remaining 20% have Y as first preference. Here Y is eliminated in the first round of the count, despite being preferred by a (different) majority to each of X and Z. Such a scenario is not fanciful: think of a centrist party that is the first preference of fewest voters but the second preference of many more on both sides. Although there are few reported examples in governmental elections, computer simulations show that IRV does not necessarily result in electing the Condorcet winner, and can behave erratically.^[52] The city of Burlington's second IRV election in 2009 failed to elect the Condorcet winner.^[53]

The two other most common methods for single winner elections (traditional runoff elections and plurality voting) are more likely than IRV to violate the Condorcet criterion.

[edit] Robert's Rules of Order

The sequential elimination method used by IRV is described in Robert's Rules of Order Newly Revised, 10th edition.^[29] 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."^[54] And then the instant runoff voting method is detailed.^[55] 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."^[56] 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^[57] and Riddick's Rules of Procedure.^[58]

[edit] Global use

[edit] Australia

Instant-runoff voting is used to elect members of the Australian House of Representatives. The Australian Senate uses a modified form of instant-runoff which combines it with a proportional representation system (technically referred to as the Single transferable vote system); candidates are eliminated until the remaining parties can be said to have a sufficient proportion of the vote to earn a seat.^[7]

The first known use of an IRV-like system in a governmental election was in 1893 in an election for the colonial government of Queensland, in Australia.^[59] 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.

IRV was introduced in 1918 after the Swan by-election, in response to the rise of the conservative 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 Corangamite by-election on 14 December 1918.^[60][61] Thomas Hare and Andrew Inglis Clark had previously introduced it in the Tasmanian House of Assembly.

Preferential voting has gradually extended to both upper and lower houses, in the federal, state and territory legislatures, and is also used in municipal elections, and most other kinds of elections as well, accepted by political parties, trade unions, churches, company boards and by voluntary bodies such as football clubs. Negotiations for disposition of preference recommendations to voters are taken very seriously by candidates because transferred preferences carry the same weight as primary votes.

[edit] Canada

IRV elected the leader of the Liberal Party of Canada in a national primary^[11] and in 2004 selected Stephen Harper as leader of the Conservative Party of Canada. It is also produces the Canadian Wheat Board.^[62]

From 1927 to 1956, the Province of Manitoba used instant-runoff voting in rural and suburban districts outside of Winnipeg (which itself used single transferable vote in multi-member electoral districts).

[edit] Fiji

IRV selects the Fijian House of Representatives.^[9]

[edit] Hong Kong

IRV is used to elect four of the 30 functional constituencies of the territory's Legislative Council, namely, the Heung Yee Kuk, the agriculture and fisheries, the insurance and the transport functional constituencies.

[edit] Ireland

IRV elects the President of Ireland.^[8]

[edit] Papua New Guinea

IRV elects the national parliament of Papua New Guinea, where it is called Limited Preferential Voting because voters are limited to three rankings.^[63]

[edit] New Zealand

IRV selects some mayors, including Wellington's.^[13]

[edit] United Kingdom

Known as Alternative Vote, IRV elects the leaders of the Labour Party and the Liberal Democrats. Its supplementary vote form elects the mayor of London and other mayors in the United Kingdom.^[12] In September 2009, Prime Minister of the United Kingdom Gordon Brown committed to hold a national referendum on IRV for House of Commons^[64] in February 2010 to replace the longstanding Westminster voting system by the "end of October 2011" if MPs approved.^[65] On 9 February 2010, MPs voted 365 to 187 to amend the Constitutional Reform and Governance Bill to hold the referendum held by October 2011.^[66] However, this part of the bill was lost during the wash-up period in preparation for the May 6 general election^[67]. The new Conservative/Liberal Democrat coalition government announced its support for a national referendum on the matter.^[68] It is to be held on 5 May 2011, if approved by Parliament,^[69]. Early polling on the referendum conducted in May and June 2010 showed a majority or plurality advantage for a "Yes" vote on use of the Alternative Vote.^[70]

[edit] United States

Since 2002, IRV has been adopted in several cities in the United States. As of February 2010, 79 elections had been held in eight counties, cities or towns: San Francisco, California; Burlington, Vermont; Takoma Park, Maryland; Cary, North Carolina; Hendersonville, North Carolina; Aspen, Colorado; Minneapolis, Minnesota;^[10] and Pierce County, Washington.^[71]

Several other cities have approved but have not yet implemented IRV. Among them are the California cities of Berkeley, Oakland and San Leandro, where IRV will be used in city elections for the first time in November 2010.^[72] Saint Paul, Minnesota, and Memphis, Tennessee will use IRV in 2011 council elections.

Not all jurisdictions have kept using IRV. Pierce County, Washington, repealed IRV by referendum in November 2009,^[73] and Burlington, Vermont repealed IRV in March 2010.^[74] The city council in Cary, North Carolina, voted to participate in an IRV pilot program in 2007, but did not do so in 2009.^[75] In 2009, voters in Aspen, Colorado, narrowly rejected an advisory measure on whether to keep IRV.^[76] In 1976 IRV was repealed after one election in Ann Arbor, Michigan.^[77]

[edit] Legal challenges in the United States

IRV has survived at least three legal challenges. A 1975 lawsuit brought against IRV in Ann Arbor, Michigan was rejected.^[78] A case against IRV in Minneapolis went to the Minnesota Supreme Court, which in June 2009 unanimously upheld the system.^[79] In April 2010, a federal judge rejected a lawsuit claiming that San Francisco's IRV system is unconstitutional.^[80]

[edit] Private organizations

IRV has been adopted by various private and non-profit associations, particularly in the Anglosphere composed of the United States, Australia, the United Kingdom, New Zealand, Ireland and Canada. In August 2009, the Academy of Motion Pictures announced that its best picture "Oscar" would be elected by IRV in 2010.^[16] The Producers Guild of America in September 2009 announced that it also would use IRV to select its best film award.^[81] Other examples in the United States include the 160,000-member American Chemical Society, 150,000-member American Psychological Association, 38,000-member American Psychiatric Association,100,000-member American Association of University Women and 56,000 member American Mensa. The American Political Science Association has long had the "alternative vote" in its constitution^[82] for electing its national President-Elect by mail under certain conditions, although there has not been a contested election for APSA President since about 1970.^[83] A list of organizations with links to their bylaws is available.^[84]

As of April 2010, at least 56 American college and university student governments have either adopted and actively use IRV, or approve and provide for its use in internal elections.^[85]

[edit] Similar systems

[edit] Runoff voting

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.

[edit] Exhaustive ballot

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.^[86] Because holding many rounds of voting on separate days is generally expensive, the exhaustive ballot is not used for large scale, public elections.

[edit] Two round systems

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 and/or counting is only necessary if no candidate receives an overall majority of votes.

[edit] Contingent vote

Top-two IRV

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 preference for those ballots is counted. As in IRV, there is only one round of voting.

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.

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 tactically, by ranking at least one a candidate they think is likely to win.

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., less 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.

[edit] In a larger runoff process

IRV may also be part of a larger runoff process:

• 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.^[87][88]
• 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.
• 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.^[89]
• 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.^[90]
• 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.^[29]

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.

[edit] See also

• 2010 articles from the Constitution Society and Electoral Reform Society summarizing the proposed change in the United Kingdom to IRV/Alternative Vote
• Alternative Vote Top-up, or Alternative Vote Plus (AV+) proposed by the Jenkins Commission (UK)
• Australian electoral system
• Ballot Access News for occasional related news in the United States
• Electoral systems of the Australian states and territories
• List of democracy and elections-related topics
• None of the above (NOTA) or Re-Open Nominations (RON)
• Preferential block voting – An instant runoff process for electing multiple seat elections.
• Table of voting systems by country
• Single transferable vote

[edit] References

[edit] External links

IRV in practice

• Advantages and disadvantages of AV from the ACE Project Electoral Design Reference Materials
• A Handbook of Electoral System Design from International IDEA
• Australian Electoral Commission Web Site
• Preferential Voting in Australia from Australian Politics.com
• San Francisco Department of Elections, California
• Alameda County Registrar of Voters, California
• City of Minneapolis, Minnesota

Demos and simulations

• Indaba.org – Demo of an IRV Ballot, including the Visual Display of a Runoff
• 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.
• OpenSTV – Open source software for computing IRV and STV
• Favourite Futurama Character Poll
• Voting System Visualizations – 2-dimensional plots of results of various systems.
• Simulation Of Various Voting Models for Close Elections Opposition article by Brian Olson.

Advocacy organizations

• Instant Runoff Voting at FairVote
  • History of IRV
• League of Women Voters of Vermont
• InstantRunoff.com
• Roosevelt Institution
• Citizens for Voter Choice :: Massachusetts
• Common Cause Massachusetts

Opposition positions

• IRV page at the Center for Range Voting
• Instant Runoff Voting Report Values and Risks Report by the N.C. Coalition for Verified Voting
• Voting methods: tutorial and essays by James Green-Armytage (for IRV, see e.g. 1 2 3 4 5)