|Part of the Politics series|
The two-round system (also known as the second ballot, runoff voting or ballotage) is a voting method used to elect a single winner, where the voter casts a single vote for their chosen candidate. Despite its name, the two-round system may resolve an election in a single round if one candidate receives enough of the vote, usually a simple majority.If no candidate receives enough of the vote in the first round, then a second round of voting is held with either just the top two candidates or all candidates who received a certain proportion of the votes.
The two-round system is used around the world for the election of legislative bodies and directly elected presidents. For example, it is used in French presidential, legislative, and departmental elections and in elections for Iran's Parliament and for the Czech Senate and for the Cuban Parliament. In Italy, it is used to elect mayors, but also to decide which party or coalition receives a majority bonus in city councils.A two-round system is used also to elect the presidents of Afghanistan, Argentina, Austria, Benin, Bolivia, Brazil, Bulgaria, Burkina Faso, Cape Verde, Chile, Colombia, Costa Rica, Croatia, Czech Republic, Cyprus, Djibouti, Dominican Republic, East Timor, Ecuador, Egypt, El Salvador, Finland, Ghana, Guatemala, Haiti, India, Iran (in elections for President of Iran and Islamic Consultative Assembly) , Indonesia, Kyrgyzstan, Liberia, Lithuania, Malawi, Moldova, North Macedonia, Peru, Poland, Portugal, Romania, Russia, Senegal, Serbia, Slovakia, Slovenia, Togo, Turkey, Ukraine, Uruguay and Zimbabwe. Historically it was used to elect the Reichstag in the German Empire between 1871 and 1918 and the Storting of Norway from 1905 to 1919, in New Zealand in the 1908 and 1911 elections, and in Israel to elect the Prime Minister in the 1996, 1999 and 2001 elections.
The two-round system is known as runoff voting in the United States, where the second round is known as a runoff election. Run-off voting is also sometimes used as a generic term to describe any method involving a number of rounds of voting, with eliminations after each round. By this broader definition the two-round system is not the only form of runoff voting, and others include the exhaustive ballot and instant runoff voting. However the subject of this article is the two-round system.
In Canada, for example, when there are more than two candidates for political party leadership they use an exhaustive ballot system (often called a runoff voting method) where one candidate must win a simple majority (over half). Candidates with the fewest votes or candidates who want to move their support to other candidates may also move to remove themselves from the next vote.
In both rounds of an election conducted using runoff voting, the voter simply marks his/her favorite candidate. If no candidate has an absolute majority of votes (i.e. more than half) in the first round, then the two candidates with the most votes proceed to a second round, from which all others are excluded. In the second round, because there are only two candidates, and absent a tie vote, one candidate will achieve an absolute majority. In the second round, each voter is entirely free to change the candidate he or she votes for, even if his/her preferred candidate has not yet been eliminated but he or she has merely changed his/her mind.
Some variants of the two-round system use a different rule for choosing candidates for the second round, and allow more than two candidates to proceed to the second round. Under such methods, it is sufficient for a candidate to receive a plurality of votes (more votes than anyone else) to be elected in the second round. In Czech and Kenyan presidential elections, the candidates in the first and second places are permitted to stand in the second round, with all other candidates eliminated, thus providing the contingency for a first- or second-place tie; a plurality is then sufficient to be elected. However, in Ghana, which also employs this contingency method, the majority requirement still holds in the second round, and a third round would be held if it isn't obtained, etc.. Under some variants of runoff voting, there is no formal rule for eliminating candidates, but candidates who receive fewer votes in the first round are expected to withdraw voluntarily.
The President of Germany was popularly elected in 1925 and 1932 by a two-round system; in the second round, a candidate could run even if they had not done so in the first round, and they did not require an absolute majority to win. In both elections, the communist candidate, Ernst Thälmann, did not withdraw and ran in the second round. In 1925, that probably ensured the election of Paul von Hindenburg (with only 48.3% of the vote), rather than Wilhelm Marx, the centrist candidate. Hindenburg had not run in the first round of the 1925 election.
Imagine an election to choose which food to eat for dessert. There are 25 people having dessert and four candidates: Ice cream, Apple pie, Fruit and Celery. Runoff voting is used to find the winner.
Round 1: In the first round of voting each diner votes for the one candidate they most prefer. The results are as follows:
Round 2: No candidate has an absolute majority of votes (in this election that would be 13) so the two candidates with the most votes, Ice cream and Fruit, proceed to a second round, while Apple pie and Celery are eliminated. Because their favorite candidates have been eliminated Apple pie and Celery supporters must now vote for one of the two remaining candidates. The sole Celery supporter is health conscious, so now gives his vote to Fruit. However Apple pie supporters are split: three prefer Ice cream and three vote for Fruit. Of those who supported Ice cream and Fruit in the first round no one decides to change their vote. The results of the second round are therefore:
Result: Ice cream now has an absolute majority so is declared the winner.
Imagine that the population of Tennessee, a state in the United States, is voting on the location of its capital. The population of Tennessee is concentrated around its four major cities, which are spread throughout the state. For this example, suppose that the entire electorate lives in these four cities, and that they would all like the capital to be established as close to their own city as possible.
The candidates for the capital are:
Round 1: In the first round of voting the results will be as follows:
Round 2: No candidate has an absolute majority in the first round (this would be greater than 50%), so Memphis and Nashville proceed to the next round, while Knoxville and Chattanooga are excluded. Both eliminated cities are closer to Nashville than they are to Memphis. Therefore, all of those who vote for either of the eliminated cities chose to vote for Nashville in the second round. None of the Memphis or Nashville supporters change their votes. The results are therefore:
Result: After round two Nashville has an absolute majority and is the winner. Note that while Nashville received only 26% of the votes and was significantly behind Memphis in the first round, it won the election by winning the second round.
Unlike the two examples above, this is from real life. In the 2002 French presidential election, the two contenders described by the media as possible winners were Jacques Chirac and Lionel Jospin, who represented the largest two political parties in France at the time. However, an exceptional number of 16 candidates were on the ballot, including even Jean-Pierre Chevènement (5.33%) and Christiane Taubira (2.32%) from the Plural Left coalition of Jospin, who refused by excess of confidence to dissuade them. Because the left vote was divided among a number of candidates as a consequence, a third contender, Jean-Marie Le Pen, unexpectedly obtained slightly more than Jospin in the first round of elections:
Several other candidates received smaller percentages of the first round vote.
Because no candidate had obtained an absolute majority of the votes in the first round, the top two candidates contested the second round. Most supporters of the parties which did not get through to the second round (and Chirac's supporters) preferred voting for Chirac rather than Le Pen, and Chirac had a very large victory.
The exhaustive ballot (EB) is similar to the two-round system, but involves more rounds of voting rather than just two. If no candidate receives an absolute majority in the first round then the candidate(s) with the fewest votes is eliminated and excluded from further ballots. The process of exclusion and reballot continues until one candidate has an absolute majority. Because voters may have to cast votes several times, EB is not used in large-scale public elections. Instead it is used in smaller contests such as the election of the presiding officer of an assembly; one long-standing example of its use is in the United Kingdom, where local associations (LCAs) of the Conservative Party use EB to elect their prospective parliamentary candidates (PPCs). Exhaustive ballot is also used by FIFA and the International Olympic Committee to select hosts. EB often elects a different winner from runoff voting. Because the two-round system excludes more than one candidate after the first round, it is possible for a candidate to be eliminated who would have gone on to win the election under EB.
A hybrid system of EB is used by the Libertarian Party of the United States to select its presidential and vice-presidential nominees. It is hybrid because of two factors: 1) "None of that Above" (NOTA) is always on the ballot, regardless of its percentage, and 2) In the first round, if no majority is reached for any candidate, the lowest candidate (other than NOTA) is eliminated, along with all other candidates who did not earn 5% of the vote. The end result of this is that the first round of voting tends to eliminate the lesser candidates, and there is always the possibility that nobody wins.
Instant-runoff voting (IRV) (also known as preferential voting or ranked-choice voting) like the exhaustive ballot involves multiple reiterative counts in which the candidate with fewest votes is eliminated each time. Whilst the exhaustive ballot and the two-round system both involve voters casting a separate vote in each round, 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 two-round system and the exhaustive ballot involve separate rounds of voting, voters can use the results of one round to decide how they will vote in the next, whereas this is not possible under IRV. Because it is necessary only to vote once, IRV, like the two-round system, is used for large-scale elections in many places such as Australian general and state elections. IRV often elects a different winner than the two-round system and tends to produce the same results as the exhaustive ballot.
Variants of instant-runoff voting can be designed to reflect the same rules as a two-round voting system. If no single candidate has an absolute majority of votes then only the two highest polling candidates progress to the second count, while all other candidates are excluded and their votes redistributed according to the recorded preferences for continuing candidates. One variant that works this way is called the Contingent vote, detailed below.
In Australia it is called preferential voting and is used to elect members of, among other institutions, the House of Representatives. In Ireland it is known as single transferable vote and is used for presidential elections and parliamentary elections.
The contingent vote is a variant of instant-runoff voting that has been used in the past in Queensland, Australia. Under the contingent vote voters cast only one vote, by ranking all of the candidates in order of preference. However it involves only two rounds of counting and uses the same rule for eliminating candidates as the two-round system. After the first round all but the two candidates with most votes are eliminated. Therefore, one candidate always achieves an absolute majority in the second round. Because of these similarities the contingent vote tends to elect the same winner as the two-round system, and often produces different results to instant-runoff voting. A variant of the contingent vote, called the supplementary vote, is used to elect some mayors in the United Kingdom. Another variant elects the President of Sri Lanka. A criticism of this method is that "it requires two polls, and gives opportunity for intrigue of various kinds."
In the United States, the Louisiana primary, introduced in Louisiana for partisan state elections in 1975 and federal elections in 1978 (with a brief return using a closed primary system in 2010), is virtually identical to the two-round system. Instead of the standard American system of primary elections to choose each party's candidate, followed by a general election contest between the winners of the primaries, the Louisiana primary allows voters to select any candidate, regardless of party affiliation. If one candidate receives an absolute majority of the votes cast, he or she is declared the winner. Otherwise, the two highest vote-winners in the first round—in effect, the first round of a two-round system—are then the only candidates whose names appear on the ballot at a runoff election, effectively requiring one candidate to win an absolute majority to take office. The key difference between the Louisiana primary and a typical two-round system is that political parties do not select the individuals using their party labels; rather, candidates can self-identify using the label of their preferred political party (or no party at all).
The state of Washington adopted a system similar to Louisiana's in 2008, which came into effect in 2010 after legal difficulties. California approved a similar system in 2010, coming into effect for the 36th congressional district election in February 2011. The system used in Washington and California is referred to as the nonpartisan blanket primary or top-two primary system. Like the Louisiana primary, candidates self-select their party label on the ballot rather than being nominated by a particular political party.
The main difference between a nonpartisan blanket primary and either a standard two-round system or the Louisiana primary is that a second round of voting is required, even if a candidate wins an absolute majority of votes in the primary.
In Australian politics (predominantly in the lower (senatorial/house) level(s)), the Two-party-preferred vote (TPP or 2PP), is the result of an election or opinion poll after preferences have been distributed to the highest two candidates, who in some cases can be independents. For the purposes of TPP, the Liberal/National Coalition is usually considered a single party, with Labor being the other major party. Typically the TPP is expressed as the percentages of votes attracted by each of the two major parties, e.g. "Coalition 45%, Labor 55%", where the values include both primary votes and preferences. The TPP is an indicator of how much swing has been attained/is required to change the result, taking into consideration preferences, which may have a significant effect on the result.
Most of the mathematical criteria by which voting methods are compared were formulated for voters with ordinal preferences. Some methods, like approval voting, request information than can't be unambiguously inferred from a single set of ordinal preferences. The two-round system is such a method, because the voters are not forced to vote according to a single ordinal preference in both rounds.
Since the two-round system requires more information from each voter than a single ordinal ballot provides, one can't fit the criteria that are formulated expressly for voters with ordinal preferences without making a generalization as to how the voters will behave. The same problem exists in Approval voting, where one has to make assumptions as to how the voters will place their approval cutoffs.
If the voters determine their preferences before the election and always vote directly consistent to them, they will emulate the contingent vote and get the same results as if they were to use that method. Therefore, in that model of voting behavior, the two-round system passes all criteria that the contingent vote passes, and fails all criteria the contingent vote fails.
Since the voters in the two-round system don't have to choose their second round votes while voting in the first round, they are able to adjust their votes as players in a game. More complex models consider voter behavior when the voters reach a game-theoretical equilibrium from which they have no incentive, as defined by their internal preferences, to further change their behavior. However, because these equilibria are complex, only partial results are known. With respect to the voters' internal preferences, the two-round system passes the majority criterion in this model, as a majority can always coordinate to elect their preferred candidate. Also, in the case of three candidates or less and a robust political equilibrium,the two-round system will pick the Condorcet winner whenever there is one, which is not the case in the Contingent vote model.
The equilibrium mentioned above is a perfect-information equilibrium and so only strictly holds in idealized conditions where every voter knows every other voter's preference. Thus it provides an upper bound on what can be achieved with rational (self-interested) coordination or knowledge of others' preferences. Since the voters almost surely won't have perfect information, it may not apply to real elections. In that matter, it is similar to the perfect competition model sometimes used in economics. To the extent that real elections approach this upper bound, large elections would do so less so than small ones, because it's less likely that a large electorate has information about all the other voters than that a small electorate has.
Runoff voting is intended to reduce the potential for eliminating "wasted" votes by tactical voting. Under the first past the post (plurality) method 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 runoff voting this tactic, known as "compromising", is sometimes unnecessary because, even if a voter's favourite candidate is eliminated in the first round, they will still have an opportunity to influence the result of the election by voting for a more popular candidate in the second round. However the tactic of compromising can still be used in runoff voting because it is sometimes necessary to compromise as a way of influencing which two candidates will survive to the second round. In order to do this it is necessary to vote for one of the three leading candidates in the first round, just as in an election held under the plurality method it is necessary to vote for one of the two leading candidates.
Runoff voting is also vulnerable to another tactic called "push over". This is a tactic by which voters vote tactically for an unpopular "push over" candidate in the first round as a way of helping their true favourite candidate win in the second round. The purpose of voting for the push over, in theory, is to ensure that it is this weak candidate, rather than a stronger rival, who survives to challenge a one's preferred candidate in the second round. But in practice, such a tactic may prove counter-productive. If so many voters give their first preferences to the "weak" candidate that it ends up winning the first round, it is highly likely they will gain enough campaign momentum to have a strong chance of winning the runoff, too, and with it, the election. At the very least, their opponent would have to start taking the so-called weak candidate seriously, particularly if the runoff follows quickly after the first round.
Runoff voting can 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 a candidate who would otherwise have stood. Runoff voting 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 ensure that another candidate they support makes it to the second round by withdrawing from the race before the first round occurs, or by never choosing to stand in the first place. By withdrawing candidates a political faction can avoid the spoiler effect, whereby a candidate "splits the vote" of its supporters. A famous example of this spoiler effect occurred in the 2002 French presidential election, when so many left-wing candidates stood in the first round that all of them were eliminated and two right-wing candidates advanced to the second round. Conversely, an important faction may have an interest in helping fund the campaign of smaller factions with a very different political agenda, so that these smaller parties end up weakening their own agenda.
Runoff voting encourages candidates to appeal to a broad cross-section of voters. This is because, in order to win an absolute majority in the second round, it is necessary for a candidate to win the support of voters whose favourite candidate has been eliminated. Under runoff voting, between rounds of voting, eliminated candidates, and the factions who previously supported them, often issue recommendations to their supporters as to whom to vote for in the second round of the contest. This means that eliminated candidates are still able to influence the result of the election. This influence leads to political bargaining between the two remaining candidates and the parties and candidates who have been eliminated, sometimes resulting in the two successful candidates making policy concessions to the less successful ones. Because it encourages conciliation and negotiation in these ways, runoff voting is advocated, in various forms, by some supporters of deliberative democracy.
Runoff voting is designed for single-seat constituencies. Therefore, like other single-seat methods, if used to elect a council or legislature it will not produce proportional representation (PR). This means that it is likely to lead to the representation of a small number of larger parties in an assembly, rather than a proliferation of small parties. In practice, runoff voting produces results very similar to those produced by the plurality method, and encourages a two-party system similar to those found in many countries that use plurality. Under a parliamentary system, it is more likely to produce single-party governments than are PR methods, which tend to produce coalition governments. While runoff voting is designed to ensure that each individual candidate elected is supported by a majority of those in their constituency, if used to elect an assembly it does not ensure this result on a national level. As in other non-PR methods, the party or coalition which wins a majority of seats will often not have the support of an absolute majority of voters across the nation.
The intention of runoff voting is that the winning candidate will have the support of an absolute majority of voters. Under the first past the post method the candidate with most votes (a plurality) wins, even if they do not have an absolute majority (more than half) of votes. The two-round system tries to overcome this problem by permitting only two candidates in the second round, so that one must receive an absolute majority of votes.
Critics argue[ who? ] that the absolute majority obtained by the winner of runoff voting is an artificial one. Instant-runoff voting and the exhaustive ballot are two other voting methods that create an absolute majority for one candidate by eliminating weaker candidates over multiple rounds. However, in cases where there are three or more strong candidates, runoff voting will sometimes produce an absolute majority for a different winner than the candidate elected by the other two.
Advocates of Condorcet methods argue[ citation needed ] that a candidate can claim to have majority support only if they are the "Condorcet winner" – that is, the candidate who would beat every other candidate in a series of one-on-one elections. In runoff voting the winning candidate is only matched, one-on-one, with one of the other candidates. When a Condorcet winner exists, he or she does not necessarily win a runoff election due to insufficient support in the first round.
Runoff advocates counter[ citation needed ] that voters' first preference is more important than lower preferences because that is where voters are putting the most effort of decision and that, unlike Condorcet methods, runoffs require a high showing among the full field of choices in addition to a strong showing in the final head-to-head competition. Condorcet methods can allow candidates to win who have minimal first-choice support and can win largely on the compromise appeal of being ranked second or third by more voters.
In large-scale public elections the two rounds of runoff voting are held on separate days, and so involve voters going to the polls twice. In smaller elections, such as those in assemblies or private organisations, it is sometimes possible to conduct both rounds in quick succession. However the fact that it involves two rounds means that, for large elections, runoff voting is more expensive than some other electoral methods. It may also lead to voter fatigue and a reduced turn-out in the second round. In runoff voting, the counting of votes in each round is simple and occurs in the same way as under the plurality methods. Ranked voting systems, such as instant-runoff voting, involve a longer, more complicated count.
One of the strongest criticisms against the two-round voting system is the cost required to conduct two ballots. The two-round voting system also has the potential to cause political instability between the two rounds of voting, adding further to the economic impact of the two-round electoral system. Under an instant run-off ballot method there is only one round.
The possibly increased costs of a two-round system have to be weighed against a debate of possibly better quality, between two clear options.
Approval voting is a single-winner electoral system where each voter may select ("approve") any number of candidates. The winner is the most-approved candidate. It is related to score voting in which voters give each option a score on a scale, and the option with the highest total of scores is selected. It is distinct from plurality voting in which a voter may choose only one option among several, whereby the option with the most votes is chosen—even absent a majority.
Plurality voting is an electoral system in which each voter is allowed to vote for only one candidate, and the candidate who polls more than any other counterpart is elected. In a system based on single-member districts, it may be called first-past-the-post (FPTP), single-choice voting, simple plurality or relative/simple majority. In a system based on multi-member districts, it may be referred to as winner-takes-all or bloc voting.
The single transferable vote (STV) is a voting system designed to achieve or closely approach proportional representation through the use of multiple-member constituencies and each voter casting a single ballot on which candidates are ranked. The preferential (ranked) balloting allows transfer of votes to produce proportionality, to form consensus behind select candidates and to avoid the waste of votes prevalent under other voting systems.
A Condorcet method is one of several election methods that elects the candidate that wins a majority of the vote in every head-to-head election against each of the other candidates, that is, a candidate preferred by more voters than any others, whenever there is such a candidate. A candidate with this property, the pairwise champion or beats-all winner, is formally called the Condorcet winner. Note that the head-to-head elections aren't necessarily done separately; a voter's preference between every pair of candidates can be found by asking them to rank the candidates, and then assuming they would vote for the candidate they ranked higher for each pairing.
Voting is a method for a group, such as a meeting or an electorate, in order to make a collective decision or express an opinion usually following discussions, debates or election campaigns. Democracies elect holders of high office by voting. Residents of a place represented by an elected official are called "constituents", and those constituents who cast a ballot for their chosen candidate are called "voters". There are different systems for collecting votes, but while many of the systems used in decision-making can also be used as electoral systems, any which cater for proportional representation can only be used in elections.
Coombs' method is a ranked voting system created by Clyde Coombs used for single-winner elections. Similarly to instant-runoff voting, it uses candidate elimination and redistribution of votes cast for that candidate until one candidate has a majority of votes.
The monotonicity criterion is a voting system criterion used to evaluate both single and multiple winner ranked voting systems. A ranked voting system is monotonic if it is neither possible to prevent the election of a candidate by ranking them higher on some of the ballots, nor possible to elect an otherwise unelected candidate by ranking them lower on some of the ballots. That is to say, in single winner elections no winner is harmed by up-ranking and no loser is helped by down-ranking. Douglas R. Woodall called the criterion mono-raise.
Vote splitting is an electoral effect in which the distribution of votes among multiple similar candidates reduces the chance of winning for any of the similar candidates, and increases the chance of winning for a dissimilar candidate.
Reversal symmetry is a voting system criterion which requires that if candidate A is the unique winner, and each voter's individual preferences are inverted, then A must not be elected. Methods that satisfy reversal symmetry include Borda count, the Kemeny-Young method, and the Schulze method. Methods that fail include Bucklin voting, instant-runoff voting and Condorcet methods that fail the Condorcet loser criterion such as Minimax.
The supplementary vote (SV) is an electoral system used to elect a single winner, in which the voter ranks the candidates in order of preference. In an election, if no candidate receives an absolute majority of first preference votes, then all but the two leading candidates are eliminated and there is a second count. In the second count, the votes of those who supported eliminated candidates are distributed among the two remaining candidates, so that one candidate achieves an absolute majority.
Like virtually all other electoral systems, in the two-round system, there is potential for both tactical voting and strategic nomination. Tactical voting is where voters do not vote in accordance with their true preferences, but instead vote insincerely in an attempt to influence the result. Runoff voting is intended as a method that reduces tactical voting, but two tactics called compromising and pushover are still possible in many circumstances. In particular voters are strongly encouraged to compromise by voting for one of the three leading candidates in the first round of an election.
The exhaustive ballot is a voting system used to elect a single winner. Under the exhaustive ballot the elector casts a single vote for their 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 contingent vote is an electoral system used to elect a single representative in which a candidate requires a majority of votes to win. It is a variation of instant-runoff voting (IRV). Under the contingent vote, the voter ranks the candidates in order of preference, and the first preference votes are counted. If no candidate has a majority, then all but the two leading candidates are eliminated and the votes received by the eliminated candidates are distributed among the two remaining candidates according to voters' preferences. This ensures that one candidate achieves a majority and is declared elected.
Multiple non-transferable vote (MNTV), also known as plurality-at-large voting or block vote, is a non-proportional voting system for electing several representatives from a single multi-member electoral district using a series of check boxes and tallying votes similar to a plurality election. Multiple winners are elected simultaneously to serve the district. Block voting is not a system for obtaining proportional representation; instead the usual result is that where the candidates divide into definitive parties the most popular party in the district sees its full slate of candidates elected, resulting in a landslide.
The Borda count is a family of single-winner election methods in which voters rank options or candidates in order of preference. The Borda count determines the outcome of a debate or the winner of an election by giving each candidate, for each ballot, a number of points corresponding to the number of candidates ranked lower. Once all votes have been counted the option or candidate with the most points is the winner. The Borda count is intended to elect broadly acceptable options or candidates, rather than those preferred by a majority, and so is often described as a consensus-based voting system rather than a majoritarian one.
Instant-runoff voting (IRV) is a type of ranked preferential voting counting method used in single-seat elections with more than two candidates. Instead of indicating support for only one candidate, voters in IRV elections can rank the candidates in order of preference. Ballots are initially counted for each voter's top choice. If a candidate has more than half of the vote based on first-choices, that candidate wins. If not, then the candidate with the fewest votes is eliminated. The voters who selected the defeated candidate as a first choice then have their votes added to the totals of their next choice. This process continues until a candidate has more than half of the votes. When the field is reduced to two, it has become an "instant runoff" that allows a comparison of the top two candidates head-to-head. Compared to plurality voting, IRV can reduce the effect of vote-splitting when multiple candidates earn support from like-minded voters.
The city of Burlington, Vermont held a mayoral election on March 3, 2009, the second election since the city approved instant-runoff voting (IRV) for use in mayoral elections in 2005. The incumbent mayor Bob Kiss, who had served since 2006, ran for reelection as the VT Progressive candidate.
An electoral system or voting system is a set of rules that determine how elections and referendums are conducted and how their results are determined. Political electoral systems are organized by governments, while non-political elections may take place in business, non-profit organisations and informal organisations. These rules govern all aspects of the voting process: when elections occur, who is allowed to vote, who can stand as a candidate, how ballots are marked and cast, how the ballots are counted, how votes translate into the election outcome, limits on campaign spending, and other factors that can affect the result. Political electoral systems are defined by constitutions and electoral laws, are typically conducted by election commissions, and can use multiple types of elections for different offices.
Ranked voting is any election voting system in which voters use a ranked ballot to select more than one candidate and to rank these choices in a sequence on the ordinal scale of 1st, 2nd, 3rd, etc. There are multiple ways in which the rankings can be counted to determine which candidate or candidates is or are elected, and these different methods may produce different results from the same set of ballots. Ranked voting is different from cardinal voting, where candidates are independently rated, rather than ranked.
Electoral systems are the rules for conducting elections. Comparisons between different systems can focus on different aspects: on suffrage or rules for voter eligibility; on candidate eligibility and the rules governing political parties; on the way elections are scheduled, sequenced, and combined; or on the rules for determining the winner within a given election.