Comparison of instant runoff voting to other voting systems
Encyclopedia
This article is a comparison of various voting systems with "Instant-runoff voting" (IRV), also called the "Alternative Vote", "preferential voting" and "ranked choice voting."
The types of various legislatures and their voting systems are given below.
, which presume that voters rank all candidates in a strict preference order, among other assumptions. No ranked preference method can satisfy all of the criteria, because some are mutually exclusive. Some of those criteria are given below, along with a list of voting systems. Voting systems that pass the criterion are labelled with a "Y", those that fail with an "N" and those that suffer an especially intolerable failure with an "IN".
Only three of these voting systems are used to elect candidates in one-winner elections held for national, regional and local government offices: First-past-the-post voting, FPTP; Instant-runoff voting
, IRV; and Two-round system
s of runoffs, RO. Because both systems involve automatic elimination of trailing candidates, every criteria failed by IRV is also failed by traditional runoffs, although IRV meets certain criteria that runoffs fail to meet.
Legend/Notes:
Voting systems that pass the criterion are labelled with a "Y", those that fail with an "N" and those that suffer an especially intolerable failure with an "IN".
Data held in the "#" column denotes the same sequence of each tabulated criterion as listed by the references' authors. Criteria in need of references is tabulated last. Additional references are needed to verify claims and to help resolve (3) disputes between claims from existing references.
Tabulated references:
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 that candidate has less than a majority of votes and even if considered the worst candidate by a majority of voters (the
"Condorcet loser"). IRV will always result in the defeat of the Condorcet loser. When used to elect legislative bodies, however, IRV can produce results that can be unrepresentative of voter preferences across the entire jurisdiction. Like all winner-take-all voting systems, IRV tends to exaggerate the number of seats won by the larger parties. For that reason some backers of proportional representation oppose IRV for legislative elections.
The "deviation from proportionality" is a linear scale that measures the degree of unfairness of a given voting system from 0 to a higher number. In the case above, 0 = perfectly proportional (seats assigned match the votes cast), and 200 = perfectly unproportional (a party with no votes gets all the seats).
Another study, (this time of 24 councils in the United Kingdom) came up with the result below:
That study adjusted the score so that 0% was perfectly proportional and 100% was the most unproportional score possible in practice.
A different study focusing just on FPTP and AV gave these results:
Like the two-round system, IRV tends to give voters a wider choice of candidates than plurality. More independent and third party candidates are likely to run because the spoiler problems are less severe. However, most jurisdictions (regardless of voting system) limit the total number of candidates by requiring deposits
, a large number of nominators, or other measures.
There are two sources of incomplete ranking:
To avoid exhaustion, Australia generally does not count exhausted ballots. But New South Wales and Queensland do count such ballots (a variant known as optional preferential voting
, or OPV). 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."
To cast a valid ballot, Australian voters must rank every candidate. Australian political parties use "how to vote" cards to encourage votes for their candidates. Without compulsory rankings, voters would have the option to stop ranking when indifferent to their remaining choices.
"Invalid ballots" are called "informal ballots" in Australia (where voting is compulsory) and "spoilt ballots" in the United Kingdom (where voting is optional).
Voting is compulsory in Australia and optional in the United Kingdom.
Most counties in the United States use voting machines to register and count their votes at the polling place. Although first choices can be counted at the polling place, AV ballots usually are counted in a central location in races without a first round majority winner. Changing the voting system by counting the vote centrally may increase the risk of fraud or may not increase the probability of fraud associated with such machine counts. FPTP need not be counted centrally.
Australia (except for ACT
) uses paper and pencils to vote and counts the votes by hand in a central location after unofficial tallies at the polling place. The fear of fraud is less.
"Tactical voting" occurs when a voter lists an "insincere preference" for a candidate due to the "spoiler effect". An "insincere preference" is when a voter deliberately gives a candidate a dishonest preference to prevent somebody winning (or another undesirable outcome).
IRV permits tactical voting if voters have complete and reliable information about the other voters' full preferences. The 2009 mayoral election
in Burlington, Vermont
provides an example where tactical voting could have happened: most supporters of the candidate who came in second (and led the first-round) preferred the Condorcet
winner (who IRV gave third place) over the IRV winner. If some of these voters had known that beforehand and insincerely raised their second-choice to first-choice, the Condorcet winner would have won the instant runoff, which these voters would have preferred.. In a three-party election where voters for both the left and right prefer the centrist candidate to stop the "enemy" candidate winning, those voters on the left and right who care more about defeating the "enemy" than electing their own candidate may cast a tactical first preference vote for the centrist candidate.
In his book Collective Decisions and Voting Nicolaus Tideman
uses real-world voting data to analyze all proposed election methods in terms of resistance to tactical voting, and states on page 194 that "alternative vote [IRV] is quite resistant to strategy."
when there are two major candidates and one or more minor candidates. In Australia, (a nation that uses IRV for its House of Representatives election) a smaller third party
co-exists with its coalition
partner
, and functions without losing seats to other parties due to vote splitting. In Australia's national elections in November 2007, at least four candidates ran in every constituency, with an average of seven, and every constituency was won with an absolute majority of votes including several where results would have been different under plurality voting.
In the United States of America (a nation where states use FPTP for allocating Electoral College
votes in Presidential election), third party and independent candidates are often characterised as "spoilers" - such as in the 2000 Bush/Gore Presidential race where Ralph Nader
was described as drawing support away from Al Gore
, allowing George W. Bush
to win.
In Ann Arbor, Michigan
arguments over IRV in letters to newspapers included the belief that IRV "gives minority candidate voters two votes," because some voters' ballots may count for their first choice in the first round and a lesser choice in a later round. This argument was addressed and rejected by a Michigan court in 1975. In Stephenson v. the Ann Arbor Board of City Canvassers, the court held that "majority preferential voting" (as IRV was then known) was not a violation of one-man, one-vote.
The "Voter Power Index" (VPI) is a linear scale that measures how powerful an individual vote is. In the case above, 0 = perfectly powerless (a vote in a very safe constituency of very large size), and 1 = perfectly powerful (a vote in a very marginal constituency of average size).
The "Voter equality" is the VPI for the least powerful fifth of voters divided by the VPI for the most powerful fifth of voters. In the case above, 0% = perfectly unequal (the least powerful fifth have no power) and 100% = perfectly equal (the least powerful fifth have the same power as the most powerful fifth).
The same study covered the United Kingdom (including Northern Ireland). The results are below:
The "average churn rate" is a percentage that measures how easy it is to remove an elected member - the higher the number, the easier to "kick the rascals out". In the case above, 0% = impossible to remove any member in any election, 100% = every member loses every seat in every election.
election (held under AV) separately from the cost of the Senate
election (held under STV
) held on the same day. The costs are below.
On 2010-05-06 the 2010 UK general election was held. The cost has not yet been released but an estimate of the cost has. It does give a quote for the cost of the House of Commons election (held under FPTP) separately from the cost of the local elections (also held under FPTP) held on the same day. The costs are below.
Because it does not require two separate votes, AV costs less than two-round primary/general or general/runoff election systems.
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."
The United States uses machines to register their votes and machines to count their votes. When voting takes place on machines relying on software, changing the voting system can lead to new 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. In 2009 the auditor [chief elections director of Washington counties] reported ongoing costs that were not necessarily balanced by the costs of eliminating runoffs for most county offices, as those elections may be needed for other offices not elected by IRV. Other jurisdictions have reported immediate cost savings.
Australia (except for ACT
) uses paper and pencils to vote and counts the votes by hand in a central location. The cost of running an election per capita is greater Australia, however, as AV involves more than one round.
The sequential elimination method used by IRV is described in Robert's Rules of Order
Newly Revised, 10th edition. 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." And then the instant runoff voting method is detailed.
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."
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
and Riddick's Rules of Procedure
.
If 90 per cent of council seats are held by a single party, opposition is effectively neutered. If 70 per cent of council seats are held by the majority party there will be some effective opposition but it can always be outvoted.
Benjamin Reilly suggests instant runoff voting eases ethnic conflict in divided societies. This was a leading reason why Papua New Guinea
adopted instant runoff voting. The result in Fiji which adopted it for the same reason were not encouraging.
John Russo, Oakland City Attorney, argued in the Oakland Tribune on July 24, 2006 that "Instant runoff voting is an antidote to the disease of negative campaigning. 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. Others state that there is a lack of evidence that such an effect occurs as often as suggested. Indeed, Lord Alexander's objections to the conclusions of the British Independent Commission on the Voting System's report cites the example of Australia saying "their politicians tend to be, if anything, more blunt and outspoken than our own."
Categories
Voting systems fall into three broad types.- Plurality/majority systems, sometimes called majoritarian.
- Proportional representation systems, sometimes called proportional.
- Semiproportional systems.
The types of various legislatures and their voting systems are given below.
| Voting system | FPTP | AV | STV Single transferable vote The single transferable vote is a voting system designed to achieve proportional representation through preferential voting. Under STV, an elector's vote is initially allocated to his or her most preferred candidate, and then, after candidates have been either elected or eliminated, any surplus or... |
PRO Party-list proportional representation Party-list proportional representation systems are a family of voting systems emphasizing proportional representation in elections in which multiple candidates are elected... |
Parallel Parallel voting Parallel voting describes a mixed voting system where voters in effect participate in two separate elections for a single chamber using different systems, and where the results in one election have little or no impact on the results of the other... |
Notes |
|---|---|---|---|---|---|---|
| Category | Majoritarian | Majoritarian | Proportional | Proportional | Semi-proportional | |
| Example legislature | UK United Kingdom The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages... HoC |
AU Australia Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area... HoR Australian House of Representatives The House of Representatives is one of the two houses of the Parliament of Australia; it is the lower house; the upper house is the Senate. Members of Parliament serve for terms of approximately three years.... |
IR Republic of Ireland Ireland , described as the Republic of Ireland , is a sovereign state in Europe occupying approximately five-sixths of the island of the same name. Its capital is Dublin. Ireland, which had a population of 4.58 million in 2011, is a constitutional republic governed as a parliamentary democracy,... DE Dáil Éireann Dáil Éireann is the lower house, but principal chamber, of the Oireachtas , which also includes the President of Ireland and Seanad Éireann . It is directly elected at least once in every five years under the system of proportional representation by means of the single transferable vote... |
NE Netherlands The Netherlands is a constituent country of the Kingdom of the Netherlands, located mainly in North-West Europe and with several islands in the Caribbean. Mainland Netherlands borders the North Sea to the north and west, Belgium to the south, and Germany to the east, and shares maritime borders... TK |
JP Japan Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south... SH House of Representatives of Japan The is the lower house of the Diet of Japan. The House of Councillors of Japan is the upper house.The House of Representatives has 480 members, elected for a four-year term. Of these, 180 members are elected from 11 multi-member constituencies by a party-list system of proportional representation,... |
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Voting system criteria
Political scientists rate voting systems using voting system criteria. Underlying these criteria are Arrow's Theorem and the Gibbard-Satterthwaite theoremGibbard-Satterthwaite theorem
The Gibbard–Satterthwaite theorem, named after Allan Gibbard and Mark Satterthwaite, is a result about the deterministic voting systems that choose a single winner using only the preferences of the voters, where each voter ranks all candidates in order of preference...
, which presume that voters rank all candidates in a strict preference order, among other assumptions. No ranked preference method can satisfy all of the criteria, because some are mutually exclusive. Some of those criteria are given below, along with a list of voting systems. Voting systems that pass the criterion are labelled with a "Y", those that fail with an "N" and those that suffer an especially intolerable failure with an "IN".
Only three of these voting systems are used to elect candidates in one-winner elections held for national, regional and local government offices: First-past-the-post voting, FPTP; Instant-runoff voting
Instant-runoff voting
Instant-runoff voting , also known as preferential voting, the alternative vote and ranked choice voting, is a voting system used to elect one winner. Voters rank candidates in order of preference, and their ballots are counted as one vote for their first choice candidate. If a candidate secures a...
, IRV; and Two-round system
Two-round system
The two-round system is a voting system used to elect a single winner where the voter casts a single vote for their chosen candidate...
s of runoffs, RO. Because both systems involve automatic elimination of trailing candidates, every criteria failed by IRV is also failed by traditional runoffs, although IRV meets certain criteria that runoffs fail to meet.
| # |
Criterion | "What does that mean?" | FPTP |
IRV Instant-runoff voting Instant-runoff voting , also known as preferential voting, the alternative vote and ranked choice voting, is a voting system used to elect one winner. Voters rank candidates in order of preference, and their ballots are counted as one vote for their first choice candidate. If a candidate secures a... |
Approval Approval voting Approval voting is a single-winner voting system used for elections. Each voter may vote for as many of the candidates as the voter wishes. The winner is the candidate receiving the most votes. Each voter may vote for any combination of candidates and may give each candidate at most one vote.The... |
Borda Borda count The Borda count is a single-winner election method in which voters rank candidates in order of preference. The Borda count determines the winner of an election by giving each candidate a certain number of points corresponding to the position in which he or she is ranked by each voter. Once all... |
Bucklin Bucklin voting Bucklin voting is a class of voting systems that can be used for single-member and multi-member districts. It is named after its original promoter, James W. Bucklin of Grand Junction, Colorado, and is also known as the Grand Junction system... |
Kemeny [-Young] |
[Minimax] Condorcet /Simpson- Kramer Minimax Condorcet In voting systems, the Minimax method is one of several Condorcet methods used for tabulating votes and determining a winner when using preferential voting in a single-winner election... |
Range Range voting Range voting is a voting system for one-seat elections under which voters score each candidate, the scores are added up, and the candidate with the highest score wins.A form of range voting was apparently used in... |
Ranked pairs/ Tideman Ranked Pairs Ranked pairs or the Tideman method is a voting system developed in 1987 by Nicolaus Tideman that selects a single winner using votes that express preferences. RP can also be used to create a sorted list of winners.... |
Two- round/ runoff Two-round system The two-round system is a voting system used to elect a single winner where the voter casts a single vote for their chosen candidate... |
Schulze Schulze method The Schulze method is a voting system developed in 1997 by Markus Schulze that selects a single winner using votes that express preferences. The method can also be used to create a sorted list of winners... |
Coombs Coombs' method The Coombs' method is a voting system created by Clyde Coombs used for single-winner elections in which each voter rank the candidates in order of preference. It is very similar to instant-runoff voting , a more common preferential voting system.-Procedures:Each voter rank-orders all of the... |
Dodgson Dodgson's method Dodgson's Method is a voting system proposed by Charles Dodgson.-Description:In Dodgson's method, each voter submits an ordered list of all candidates according to their own preference . The winner is defined to be the candidate for whom we need to perform the minimum number of pairwise swaps ... |
Nanson Nanson's method The Borda count can be combined with an Instant Runoff procedure to create hybrid election methods that are called Nanson method and Baldwin method.- Nanson method :The Nanson method is based on the original work of the mathematician Edward J... |
Copeland Copeland's method Copeland's method or Copeland's pairwise aggregation method is a Condorcet method in which candidates are ordered by the number of pairwise victories, minus the number of pairwise defeats.... |
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| 1.2 | Condorcet [Winner Condorcet criterion The Condorcet candidate or Condorcet winner of an election is the candidate who, when compared with every other candidate, is preferred by more voters. Informally, the Condorcet winner is the person who would win a two-candidate election against each of the other candidates... ] |
OR |
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| 1.3 | [Absolute] Majority [Winner Majority criterion The majority criterion is a single-winner voting system criterion, used to compare such systems. The criterion states that "if one candidate is preferred by a majority of voters, then that candidate must win".... ] |
As a special case of the Condorcet Winner, to fail this means to also fail the Condorcet Winner. OR |
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| 1.3j | Mutual Majority / Majority for Solid Coalitions / Generalized Majority Mutual majority criterion The mutual majority criterion is a criterion used to compare voting systems. It is also known as the majority criterion for solid coalitions and the generalized majority criterion... |
Similar to but more strict than the Majority Winner. |
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| 1.4 | Condorcet Loser / Borda Condorcet loser criterion In single-winner voting system theory, the Condorcet loser criterion is a measure for differentiating voting systems. It implies the majority loser criterion.... |
OR |
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| 1.5 | Absolute Loser / Majority Loser Majority loser criterion The majority loser criterion is a criterion to evaluate single-winner voting systems. The criterion states that if a majority of voters prefers every other candidate over a given candidate, then that candidate must not win.... |
As a special case of the Condorcet Loser, to fail this means to also fail the Condorcet Loser. OR |
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| 1.6 | Pareto / Dominated Candidate Pareto efficiency Pareto efficiency, or Pareto optimality, is a concept in economics with applications in engineering and social sciences. The term is named after Vilfredo Pareto, an Italian economist who used the concept in his studies of economic efficiency and income distribution.Given an initial allocation of... |
OR |
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| 2.1 | Monotonicity / Additional Support / Mono-Raise / [Non-]Negative Responsiveness Monotonicity criterion The monotonicity criterion is a voting system criterion used to analyze both single and multiple winner voting systems. A voting system is monotonic if it satisfies one of the definitions of the monotonicity criterion, given below.Douglas R... |
To fail this, it is likely to also fail Participation / No-Show. OR |
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| 2.2 | Consistency / Reinforcement / Multiple Districts / Separability / Convexity Consistency criterion A voting system is consistent if, when the electorate is divided arbitrarily into two parts and separate elections in each part result in the same choice being selected, an election of the entire electorate also selects that alternative... |
OR |
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| 2.4 | Participation / No-Show Participation criterion The participation criterion is a voting system criterion. It is also known as the "no show paradox". It has been defined as follows:* In a deterministic framework, the participation criterion says that the addition of a ballot, where candidate A is strictly preferred to candidate B, to an existing... |
As an extreme version of the Truncation, to fail this, it is likely to also fail Truncation & Twin (neither tabulated). OR |
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| 2.6 | Independence of Irrelevant Alternatives (IIA/IIR) / Subset Choice (SCC) Independence of irrelevant alternatives Independence of irrelevant alternatives is an axiom of decision theory and various social sciences.The word is used in different meanings in different contexts.... |
OR (eg.vote splitting Vote splitting 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.... & spoiler effect Spoiler effect The spoiler effect describes the effect a minor party candidate with little chance of winning has in a close election, when that candidate's presence in the election draws votes from a major candidate similar to them, thereby causing a candidate dissimilar to them to win the election... ) |
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| 2.8 | Strategic Voting / Tactical Voting Tactical voting In voting systems, tactical voting occurs, in elections with more than two viable candidates, when a voter supports a candidate other than his or her sincere preference in order to prevent an undesirable outcome.It has been shown by the Gibbard-Satterthwaite theorem that any voting method which is... |
OR |
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| 3.a | Resolvability Resolvability criterion Resolvability criterion can refer to any voting system criterion that ensures a low possibility of tie votes.#Nicolaus Tideman's version of the criterion demands that if and only if for every winner in a result, a vote exists, such that when added, makes that winner unique.#Douglas R... |
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| 3.c | Reversal symmetry Reversal symmetry 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... |
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| 3.e | Independence of Clones Independence of clones criterion In voting systems theory, the independence of clones criterion measures an election method's robustness to strategic nomination. Nicolaus Tideman first formulated the criterion, which states that the addition of a candidate identical to one already present in an election will not cause the winner... |
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| 3.p | Polynomial [run]time | Cobham's thesis Cobham's Thesis Cobham's thesis, also known as Cobham–Edmonds thesis , asserts that computational problems can be feasibly computed on some computational device only if they can be computed in polynomial time; that is, if they lie in the complexity class P.Formally, to say that a problem can be solved in... states that polynomial time is a synonym for "tractable", "feasible", "efficient", or "fast". |
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| 9.z | Later-No-Harm Later-no-harm criterion The later-no-harm criterion is a voting system criterion formulated by Douglas Woodall. The criterion is satisfied if, in any election, a voter giving an additional ranking or positive rating to a less preferred candidate cannot cause a more preferred candidate to lose.- Complying methods :Single... |
Coombs' method Coombs' method The Coombs' method is a voting system created by Clyde Coombs used for single-winner elections in which each voter rank the candidates in order of preference. It is very similar to instant-runoff voting , a more common preferential voting system.-Procedures:Each voter rank-orders all of the... is defined only for situations where each voter casts a complete ranking of all candidates. |
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| |Total Especially Intolerable Failures | "there seems to be a wide consensus that a voting procedure which is susceptible to a 'cardinal sin' (i.e.which may elect a Pareto-dominated candidate, or elect an Absolute Loser, or display non-monotonicity, or not elect an Absolute Winner) should be disqualified as a reasonable voting procedure regardless of the probability that these paradoxes may occur." | 3 | 1 | 5 | 2 | 1 | 0 | 3 | 4 | 0 | 2 | 0 | 1 | 3.5 | 1 | 0 | |
| |Total Failures | 8 | 7 | 9 | 7 | 9 | 6.5 | 10 | 7 | 4 | 9 | 4 | 8 | 11.5 | 7 | 6.5 | ||
| # | Criterion | "What does that mean?" | FPTP | IRV Instant-runoff voting Instant-runoff voting , also known as preferential voting, the alternative vote and ranked choice voting, is a voting system used to elect one winner. Voters rank candidates in order of preference, and their ballots are counted as one vote for their first choice candidate. If a candidate secures a... |
Approval Approval voting Approval voting is a single-winner voting system used for elections. Each voter may vote for as many of the candidates as the voter wishes. The winner is the candidate receiving the most votes. Each voter may vote for any combination of candidates and may give each candidate at most one vote.The... |
Borda Borda count The Borda count is a single-winner election method in which voters rank candidates in order of preference. The Borda count determines the winner of an election by giving each candidate a certain number of points corresponding to the position in which he or she is ranked by each voter. Once all... |
Bucklin Bucklin voting Bucklin voting is a class of voting systems that can be used for single-member and multi-member districts. It is named after its original promoter, James W. Bucklin of Grand Junction, Colorado, and is also known as the Grand Junction system... |
Kemeny [-Young] |
[Minimax] Condorcet /Simpson- Kramer Minimax Condorcet In voting systems, the Minimax method is one of several Condorcet methods used for tabulating votes and determining a winner when using preferential voting in a single-winner election... |
Range Range voting Range voting is a voting system for one-seat elections under which voters score each candidate, the scores are added up, and the candidate with the highest score wins.A form of range voting was apparently used in... |
Ranked pairs/ Tideman Ranked Pairs Ranked pairs or the Tideman method is a voting system developed in 1987 by Nicolaus Tideman that selects a single winner using votes that express preferences. RP can also be used to create a sorted list of winners.... |
Two- round/ runoff Two-round system The two-round system is a voting system used to elect a single winner where the voter casts a single vote for their chosen candidate... |
Schulze Schulze method The Schulze method is a voting system developed in 1997 by Markus Schulze that selects a single winner using votes that express preferences. The method can also be used to create a sorted list of winners... |
Coombs Coombs' method The Coombs' method is a voting system created by Clyde Coombs used for single-winner elections in which each voter rank the candidates in order of preference. It is very similar to instant-runoff voting , a more common preferential voting system.-Procedures:Each voter rank-orders all of the... |
Dodgson Dodgson's method Dodgson's Method is a voting system proposed by Charles Dodgson.-Description:In Dodgson's method, each voter submits an ordered list of all candidates according to their own preference . The winner is defined to be the candidate for whom we need to perform the minimum number of pairwise swaps ... |
Nanson Nanson's method The Borda count can be combined with an Instant Runoff procedure to create hybrid election methods that are called Nanson method and Baldwin method.- Nanson method :The Nanson method is based on the original work of the mathematician Edward J... |
Copeland Copeland's method Copeland's method or Copeland's pairwise aggregation method is a Condorcet method in which candidates are ordered by the number of pairwise victories, minus the number of pairwise defeats.... |
Legend/Notes:
Voting systems that pass the criterion are labelled with a "Y", those that fail with an "N" and those that suffer an especially intolerable failure with an "IN".
Data held in the "#" column denotes the same sequence of each tabulated criterion as listed by the references' authors. Criteria in need of references is tabulated last. Additional references are needed to verify claims and to help resolve (3) disputes between claims from existing references.
Tabulated references:
Are the results proportional?
| Criterion | What does that mean? | FPTP | AV | Notes |
|---|---|---|---|---|
| Is it proportional? | "Does the number of seats awarded match the number of votes cast?" | See below | ||
The intention of IRV is to find one candidate acceptable to a majority
Majority
A majority is a subset of a group consisting of more than half of its members. This can be compared to a plurality, which is a subset larger than any other subset; i.e. a plurality is not necessarily a majority as the largest subset may consist of less than half the group's population...
of voters. It is intended as an improvement on the 'first-past-the-post
First-past-the-post
First-past-the-post voting refers to an election won by the candidate with the most votes. The winning potato candidate does not necessarily receive an absolute majority of all votes cast.-Overview:...
' (plurality) voting system. Under 'first-past-the-post' the candidate with the most votes wins, even if that candidate has less than a majority of votes and even if considered the worst candidate by a majority of voters (the
"Condorcet loser"). IRV will always result in the defeat of the Condorcet loser. When used to elect legislative bodies, however, IRV can produce results that can be unrepresentative of voter preferences across the entire jurisdiction. Like all winner-take-all voting systems, IRV tends to exaggerate the number of seats won by the larger parties. For that reason some backers of proportional representation oppose IRV for legislative elections.
How unproportional are the results?
The "deviation from proportionality" for four systems since 1945 are as follows:| Criterion | What does that mean? | FPTP | AV | STV Single transferable vote The single transferable vote is a voting system designed to achieve proportional representation through preferential voting. Under STV, an elector's vote is initially allocated to his or her most preferred candidate, and then, after candidates have been either elected or eliminated, any surplus or... |
PRO Party-list proportional representation Party-list proportional representation systems are a family of voting systems emphasizing proportional representation in elections in which multiple candidates are elected... |
Notes |
|---|---|---|---|---|---|---|
| Deviation from proportionality | "How unproportional is the voting system?" | 29.4 | 27.3 | 12.0 | 5.22 | See below |
The "deviation from proportionality" is a linear scale that measures the degree of unfairness of a given voting system from 0 to a higher number. In the case above, 0 = perfectly proportional (seats assigned match the votes cast), and 200 = perfectly unproportional (a party with no votes gets all the seats).
Another study, (this time of 24 councils in the United Kingdom) came up with the result below:
| Criterion | What does that mean? | FPTP | AV | STV Single transferable vote The single transferable vote is a voting system designed to achieve proportional representation through preferential voting. Under STV, an elector's vote is initially allocated to his or her most preferred candidate, and then, after candidates have been either elected or eliminated, any surplus or... |
PRO Party-list proportional representation Party-list proportional representation systems are a family of voting systems emphasizing proportional representation in elections in which multiple candidates are elected... |
AMS Additional Member System The Additional Member System is the term used in the United Kingdom for the mixed member proportional representation voting system used in Scotland, Wales and the London Assembly.... |
Notes |
|---|---|---|---|---|---|---|---|
| Deviation from proportionality (adjusted scale) | "How unproportional is the voting system?" | 22% | 16% | 7% | 7% | 3% | See below |
That study adjusted the score so that 0% was perfectly proportional and 100% was the most unproportional score possible in practice.
What are the results under different systems?
How well do different political parties do under different systems? Some results are given below:| Criterion | What does that mean? | FPTP | AV | STV Single transferable vote The single transferable vote is a voting system designed to achieve proportional representation through preferential voting. Under STV, an elector's vote is initially allocated to his or her most preferred candidate, and then, after candidates have been either elected or eliminated, any surplus or... |
PRO Party-list proportional representation Party-list proportional representation systems are a family of voting systems emphasizing proportional representation in elections in which multiple candidates are elected... |
Notes |
|---|---|---|---|---|---|---|
| UK Conservative 2010 seats | "How many seats would Conservatives Conservative Party (UK) The Conservative Party, formally the Conservative and Unionist Party, is a centre-right political party in the United Kingdom that adheres to the philosophies of conservatism and British unionism. It is the largest political party in the UK, and is currently the largest single party in the House... have in 2010 under this system?" |
306 | 281 | 246 | 234 | |
| UK Labour 2010 seats | "How many seats would Labour Labour Party (UK) The Labour Party is a centre-left democratic socialist party in the United Kingdom. It surpassed the Liberal Party in general elections during the early 1920s, forming minority governments under Ramsay MacDonald in 1924 and 1929-1931. The party was in a wartime coalition from 1940 to 1945, after... have in 2010 under this system?" |
258 | 262 | 207 | 189 | |
| UK Liberal 2010 seats | "How many seats would Liberals Liberal Democrats The Liberal Democrats are a social liberal political party in the United Kingdom which supports constitutional and electoral reform, progressive taxation, wealth taxation, human rights laws, cultural liberalism, banking reform and civil liberties .The party was formed in 1988 by a merger of the... have in 2010 under this system?" |
57 | 79 | 162 | 149 |
A different study focusing just on FPTP and AV gave these results:
| Criterion | What does that mean? | FPTP | AV | Notes |
|---|---|---|---|---|
| UK Conservative 1983 seats | "How many seats would Conservatives Conservative Party (UK) The Conservative Party, formally the Conservative and Unionist Party, is a centre-right political party in the United Kingdom that adheres to the philosophies of conservatism and British unionism. It is the largest political party in the UK, and is currently the largest single party in the House... have in 1983 United Kingdom general election, 1983 The 1983 United Kingdom general election was held on 9 June 1983. It gave the Conservative Party under Margaret Thatcher the most decisive election victory since that of Labour in 1945... under this system?" |
397 | 391 | |
| UK Labour 1983 seats | "How many seats would Labour Labour Party (UK) The Labour Party is a centre-left democratic socialist party in the United Kingdom. It surpassed the Liberal Party in general elections during the early 1920s, forming minority governments under Ramsay MacDonald in 1924 and 1929-1931. The party was in a wartime coalition from 1940 to 1945, after... have in 1983 United Kingdom general election, 1983 The 1983 United Kingdom general election was held on 9 June 1983. It gave the Conservative Party under Margaret Thatcher the most decisive election victory since that of Labour in 1945... under this system?" |
209 | 190 | |
| UK Liberal 1983 seats | "How many seats would Liberals Liberal Democrats The Liberal Democrats are a social liberal political party in the United Kingdom which supports constitutional and electoral reform, progressive taxation, wealth taxation, human rights laws, cultural liberalism, banking reform and civil liberties .The party was formed in 1988 by a merger of the... have in 1983 United Kingdom general election, 1983 The 1983 United Kingdom general election was held on 9 June 1983. It gave the Conservative Party under Margaret Thatcher the most decisive election victory since that of Labour in 1945... under this system?" |
23 | 48 | |
| UK Conservative 1987 seats | "How many seats would Conservatives Conservative Party (UK) The Conservative Party, formally the Conservative and Unionist Party, is a centre-right political party in the United Kingdom that adheres to the philosophies of conservatism and British unionism. It is the largest political party in the UK, and is currently the largest single party in the House... have in 1987 United Kingdom general election, 1987 The United Kingdom general election of 1987 was held on 11 June 1987, to elect 650 members to the British House of Commons. The election was the third consecutive election victory for the Conservative Party under the leadership of Margaret Thatcher, who became the first Prime Minister since the 2nd... under this system?" |
376 | 381 | |
| UK Labour 1987 seats | "How many seats would Labour Labour Party (UK) The Labour Party is a centre-left democratic socialist party in the United Kingdom. It surpassed the Liberal Party in general elections during the early 1920s, forming minority governments under Ramsay MacDonald in 1924 and 1929-1931. The party was in a wartime coalition from 1940 to 1945, after... have in 1987 United Kingdom general election, 1987 The United Kingdom general election of 1987 was held on 11 June 1987, to elect 650 members to the British House of Commons. The election was the third consecutive election victory for the Conservative Party under the leadership of Margaret Thatcher, who became the first Prime Minister since the 2nd... under this system?" |
229 | 202 | |
| UK Liberal 1987 seats | "How many seats would Liberals Liberal Democrats The Liberal Democrats are a social liberal political party in the United Kingdom which supports constitutional and electoral reform, progressive taxation, wealth taxation, human rights laws, cultural liberalism, banking reform and civil liberties .The party was formed in 1988 by a merger of the... have in 1987 United Kingdom general election, 1987 The United Kingdom general election of 1987 was held on 11 June 1987, to elect 650 members to the British House of Commons. The election was the third consecutive election victory for the Conservative Party under the leadership of Margaret Thatcher, who became the first Prime Minister since the 2nd... under this system?" |
22 | 44 | |
| UK Conservative 1992 seats | "How many seats would Conservatives Conservative Party (UK) The Conservative Party, formally the Conservative and Unionist Party, is a centre-right political party in the United Kingdom that adheres to the philosophies of conservatism and British unionism. It is the largest political party in the UK, and is currently the largest single party in the House... have in 1992 United Kingdom general election, 1992 The United Kingdom general election of 1992 was held on 9 April 1992, and was the fourth consecutive victory for the Conservative Party. This election result was one of the biggest surprises in 20th Century politics, as polling leading up to the day of the election showed Labour under leader Neil... under this system?" |
336 | 328 | |
| UK Labour 1992 seats | "How many seats would Labour Labour Party (UK) The Labour Party is a centre-left democratic socialist party in the United Kingdom. It surpassed the Liberal Party in general elections during the early 1920s, forming minority governments under Ramsay MacDonald in 1924 and 1929-1931. The party was in a wartime coalition from 1940 to 1945, after... have in 1992 United Kingdom general election, 1992 The United Kingdom general election of 1992 was held on 9 April 1992, and was the fourth consecutive victory for the Conservative Party. This election result was one of the biggest surprises in 20th Century politics, as polling leading up to the day of the election showed Labour under leader Neil... under this system?" |
271 | 268 | |
| UK Liberal 1992 seats | "How many seats would Liberals Liberal Democrats The Liberal Democrats are a social liberal political party in the United Kingdom which supports constitutional and electoral reform, progressive taxation, wealth taxation, human rights laws, cultural liberalism, banking reform and civil liberties .The party was formed in 1988 by a merger of the... have in 1992 United Kingdom general election, 1992 The United Kingdom general election of 1992 was held on 9 April 1992, and was the fourth consecutive victory for the Conservative Party. This election result was one of the biggest surprises in 20th Century politics, as polling leading up to the day of the election showed Labour under leader Neil... under this system?" |
20 | 31 | |
| UK Conservative 1997 seats | "How many seats would Conservatives Conservative Party (UK) The Conservative Party, formally the Conservative and Unionist Party, is a centre-right political party in the United Kingdom that adheres to the philosophies of conservatism and British unionism. It is the largest political party in the UK, and is currently the largest single party in the House... have in 1997 United Kingdom general election, 1997 The United Kingdom general election, 1997 was held on 1 May 1997, more than five years after the previous election on 9 April 1992, to elect 659 members to the British House of Commons. The Labour Party ended its 18 years in opposition under the leadership of Tony Blair, and won the general... under this system?" |
165 | 70 | |
| UK Labour 1997 seats | "How many seats would Labour Labour Party (UK) The Labour Party is a centre-left democratic socialist party in the United Kingdom. It surpassed the Liberal Party in general elections during the early 1920s, forming minority governments under Ramsay MacDonald in 1924 and 1929-1931. The party was in a wartime coalition from 1940 to 1945, after... have in 1997 United Kingdom general election, 1997 The United Kingdom general election, 1997 was held on 1 May 1997, more than five years after the previous election on 9 April 1992, to elect 659 members to the British House of Commons. The Labour Party ended its 18 years in opposition under the leadership of Tony Blair, and won the general... under this system?" |
419 | 445 | |
| UK Liberal 1997 seats | "How many seats would Liberals Liberal Democrats The Liberal Democrats are a social liberal political party in the United Kingdom which supports constitutional and electoral reform, progressive taxation, wealth taxation, human rights laws, cultural liberalism, banking reform and civil liberties .The party was formed in 1988 by a merger of the... have in 1997 United Kingdom general election, 1997 The United Kingdom general election, 1997 was held on 1 May 1997, more than five years after the previous election on 9 April 1992, to elect 659 members to the British House of Commons. The Labour Party ended its 18 years in opposition under the leadership of Tony Blair, and won the general... under this system?" |
46 | 115 | |
| UK Conservative 2001 seats | "How many seats would Conservatives Conservative Party (UK) The Conservative Party, formally the Conservative and Unionist Party, is a centre-right political party in the United Kingdom that adheres to the philosophies of conservatism and British unionism. It is the largest political party in the UK, and is currently the largest single party in the House... have in 2001 United Kingdom general election, 2001 The United Kingdom general election, 2001 was held on Thursday 7 June 2001 to elect 659 members to the British House of Commons. It was dubbed "the quiet landslide" by the media, as the Labour Party was re-elected with another landslide result and only suffered a net loss of 6 seats... under this system?" |
166 | 140 | |
| UK Labour 2001 seats | "How many seats would Labour Labour Party (UK) The Labour Party is a centre-left democratic socialist party in the United Kingdom. It surpassed the Liberal Party in general elections during the early 1920s, forming minority governments under Ramsay MacDonald in 1924 and 1929-1931. The party was in a wartime coalition from 1940 to 1945, after... have in 2001 United Kingdom general election, 2001 The United Kingdom general election, 2001 was held on Thursday 7 June 2001 to elect 659 members to the British House of Commons. It was dubbed "the quiet landslide" by the media, as the Labour Party was re-elected with another landslide result and only suffered a net loss of 6 seats... under this system?" |
413 | 423 | |
| UK Liberal 2001 seats | "How many seats would Liberals Liberal Democrats The Liberal Democrats are a social liberal political party in the United Kingdom which supports constitutional and electoral reform, progressive taxation, wealth taxation, human rights laws, cultural liberalism, banking reform and civil liberties .The party was formed in 1988 by a merger of the... have in 2001 United Kingdom general election, 2001 The United Kingdom general election, 2001 was held on Thursday 7 June 2001 to elect 659 members to the British House of Commons. It was dubbed "the quiet landslide" by the media, as the Labour Party was re-elected with another landslide result and only suffered a net loss of 6 seats... under this system?" |
52 | 68 | |
| UK Conservative 2005 seats | "How many seats would Conservatives Conservative Party (UK) The Conservative Party, formally the Conservative and Unionist Party, is a centre-right political party in the United Kingdom that adheres to the philosophies of conservatism and British unionism. It is the largest political party in the UK, and is currently the largest single party in the House... have in 2005 United Kingdom general election, 2005 The United Kingdom general election of 2005 was held on Thursday, 5 May 2005 to elect 646 members to the British House of Commons. The Labour Party under Tony Blair won its third consecutive victory, but with a majority of 66, reduced from 160.... under this system?" |
198 | 171 | |
| UK Labour 2005 seats | "How many seats would Labour Labour Party (UK) The Labour Party is a centre-left democratic socialist party in the United Kingdom. It surpassed the Liberal Party in general elections during the early 1920s, forming minority governments under Ramsay MacDonald in 1924 and 1929-1931. The party was in a wartime coalition from 1940 to 1945, after... have in 2005 United Kingdom general election, 2005 The United Kingdom general election of 2005 was held on Thursday, 5 May 2005 to elect 646 members to the British House of Commons. The Labour Party under Tony Blair won its third consecutive victory, but with a majority of 66, reduced from 160.... under this system?" |
356 | 377 | |
| UK Liberal 2005 seats | "How many seats would Liberals Liberal Democrats The Liberal Democrats are a social liberal political party in the United Kingdom which supports constitutional and electoral reform, progressive taxation, wealth taxation, human rights laws, cultural liberalism, banking reform and civil liberties .The party was formed in 1988 by a merger of the... have in 2005 United Kingdom general election, 2005 The United Kingdom general election of 2005 was held on Thursday, 5 May 2005 to elect 646 members to the British House of Commons. The Labour Party under Tony Blair won its third consecutive victory, but with a majority of 66, reduced from 160.... under this system?" |
62 | 68 |
Are the results decisive?
How decisive are elections under different systems? Some results are given below:| Criterion | What does that mean? | FPTP | AV | Notes |
|---|---|---|---|---|
| 1983 UK election outcome United Kingdom general election, 1983 The 1983 United Kingdom general election was held on 9 June 1983. It gave the Conservative Party under Margaret Thatcher the most decisive election victory since that of Labour in 1945... |
"Would there have been a "hung parliament Hung parliament In a two-party parliamentary system of government, a hung parliament occurs when neither major political party has an absolute majority of seats in the parliament . It is also less commonly known as a balanced parliament or a legislature under no overall control... " in 1983 in the UK under this system?" |
|||
| 1987 UK election outcome United Kingdom general election, 1987 The United Kingdom general election of 1987 was held on 11 June 1987, to elect 650 members to the British House of Commons. The election was the third consecutive election victory for the Conservative Party under the leadership of Margaret Thatcher, who became the first Prime Minister since the 2nd... |
"Would there have been a "hung parliament Hung parliament In a two-party parliamentary system of government, a hung parliament occurs when neither major political party has an absolute majority of seats in the parliament . It is also less commonly known as a balanced parliament or a legislature under no overall control... " in 1987 in the UK under this system?" |
|||
| 1992 UK election outcome United Kingdom general election, 1992 The United Kingdom general election of 1992 was held on 9 April 1992, and was the fourth consecutive victory for the Conservative Party. This election result was one of the biggest surprises in 20th Century politics, as polling leading up to the day of the election showed Labour under leader Neil... |
"Would there have been a "hung parliament Hung parliament In a two-party parliamentary system of government, a hung parliament occurs when neither major political party has an absolute majority of seats in the parliament . It is also less commonly known as a balanced parliament or a legislature under no overall control... " in 1992 in the UK under this system?" |
|||
| 1997 UK election outcome United Kingdom general election, 1997 The United Kingdom general election, 1997 was held on 1 May 1997, more than five years after the previous election on 9 April 1992, to elect 659 members to the British House of Commons. The Labour Party ended its 18 years in opposition under the leadership of Tony Blair, and won the general... |
"Would there have been a "hung parliament Hung parliament In a two-party parliamentary system of government, a hung parliament occurs when neither major political party has an absolute majority of seats in the parliament . It is also less commonly known as a balanced parliament or a legislature under no overall control... " in 1997 in the UK under this system?" |
|||
| 2001 UK election outcome United Kingdom general election, 2001 The United Kingdom general election, 2001 was held on Thursday 7 June 2001 to elect 659 members to the British House of Commons. It was dubbed "the quiet landslide" by the media, as the Labour Party was re-elected with another landslide result and only suffered a net loss of 6 seats... |
"Would there have been a "hung parliament Hung parliament In a two-party parliamentary system of government, a hung parliament occurs when neither major political party has an absolute majority of seats in the parliament . It is also less commonly known as a balanced parliament or a legislature under no overall control... " in 2001 in the UK under this system?" |
|||
| 2005 UK election outcome United Kingdom general election, 2005 The United Kingdom general election of 2005 was held on Thursday, 5 May 2005 to elect 646 members to the British House of Commons. The Labour Party under Tony Blair won its third consecutive victory, but with a majority of 66, reduced from 160.... |
"Would there have been a "hung parliament Hung parliament In a two-party parliamentary system of government, a hung parliament occurs when neither major political party has an absolute majority of seats in the parliament . It is also less commonly known as a balanced parliament or a legislature under no overall control... " in 2005 in the UK under this system?" |
|||
| 2010 UK election outcome | "Would there have been a "hung parliament Hung parliament In a two-party parliamentary system of government, a hung parliament occurs when neither major political party has an absolute majority of seats in the parliament . It is also less commonly known as a balanced parliament or a legislature under no overall control... " in 2010 in the UK under this system?" |
|||
No overall majority
"No overall majority" is achieved when no single party has more seats than the other parties combined. How often does this happen? Some results are below:| Criterion | What does that mean? | FPTP | AV | STV Single transferable vote The single transferable vote is a voting system designed to achieve proportional representation through preferential voting. Under STV, an elector's vote is initially allocated to his or her most preferred candidate, and then, after candidates have been either elected or eliminated, any surplus or... |
PRO Party-list proportional representation Party-list proportional representation systems are a family of voting systems emphasizing proportional representation in elections in which multiple candidates are elected... |
AMS Additional Member System The Additional Member System is the term used in the United Kingdom for the mixed member proportional representation voting system used in Scotland, Wales and the London Assembly.... |
Notes |
|---|---|---|---|---|---|---|---|
| No overall majority | "How often will no single party have more seats than the other parties combined?" | 16.7% (4/24) | 16.7% (4/24) | 37.5% (9/24) | 37.5% (9/24) | 54.1% (13/24) |
Number of ballots per voter
The "number of ballots per voter" is the number of times a vote has to complete a single ballot.| Criterion | What does that mean? | Single-round Plurality (inc. FPTP) |
Preferential (inc. AV) |
Multiple-round (inc. EB Exhaustive ballot The exhaustive ballot is a voting system used to elect a single winner. Under the exhaustive ballot the elector simply casts a single vote for his or her favorite candidate. However if no candidate is supported by an overall majority of votes then the candidate with the fewest votes is eliminated... and RO Two-round system The two-round system is a voting system used to elect a single winner where the voter casts a single vote for their chosen candidate... ) |
Notes |
|---|---|---|---|---|---|
| Number of ballots per voter | "How many times does a voter have to complete a single ballot?" | Once | Once | More than once | |
Voter choice
"Voter choice" is the number of candidates on the ballot.| Criterion | What does that mean? | Single-round Plurality (inc. FPTP) |
Preferential (inc. AV) |
Multiple-round (inc. EB Exhaustive ballot The exhaustive ballot is a voting system used to elect a single winner. Under the exhaustive ballot the elector simply casts a single vote for his or her favorite candidate. However if no candidate is supported by an overall majority of votes then the candidate with the fewest votes is eliminated... and RO Two-round system The two-round system is a voting system used to elect a single winner where the voter casts a single vote for their chosen candidate... ) |
Notes |
|---|---|---|---|---|---|
| Voter choice | "Which system gives the higher number of candidates" | Plurality gives less candidates than preferential or multiple-round | Preferential gives more candidates than plurality | Multiple-round gives more candidates than plurality | See below |
Like the two-round system, IRV tends to give voters a wider choice of candidates than plurality. More independent and third party candidates are likely to run because the spoiler problems are less severe. However, most jurisdictions (regardless of voting system) limit the total number of candidates by requiring deposits
Deposit (politics)
A deposit is a sum of money that a candidate must pay in return for the right to stand for election to certain political offices, particularly seats in legislatures.-United Kingdom:...
, a large number of nominators, or other measures.
Voter exhaustion
"Incomplete ranking" occurs when a voter fails to list a preference for all the candidates. The ballots on which incomplete ranking has occurred are called "exhausted ballots". The result is referred to as "voter exhaustion".| Criterion | What does that mean? | FPTP | AV (with OPV Optional Preferential Voting Optional Preferential Voting is a system of vote-casting used in the states of Queensland and New South Wales in the Commonwealth of Australia. Most Australian elections are run under full-preference preferential voting, where all candidates must be numbered in order of the preference of the... ) |
AV (without OPV Optional Preferential Voting Optional Preferential Voting is a system of vote-casting used in the states of Queensland and New South Wales in the Commonwealth of Australia. Most Australian elections are run under full-preference preferential voting, where all candidates must be numbered in order of the preference of the... ) |
Notes |
|---|---|---|---|---|---|
| Exhausted ballots | "Does the system prevent exhausted ballots being counted?" | FPTP fails exhaustion by definition. AV fails it if exhausted ballots are counted. See below. | |||
There are two sources of incomplete ranking:
- Some implementations don't allow complete ranking, either due to voting machine limitations or other reasons; for example, San Francisco allows only three ranks, even with over twenty candidates.
- Some voters may simply choose not to rank all the candidates.
To avoid exhaustion, Australia generally does not count exhausted ballots. But New South Wales and Queensland do count such ballots (a variant known as optional preferential voting
Optional Preferential Voting
Optional Preferential Voting is a system of vote-casting used in the states of Queensland and New South Wales in the Commonwealth of Australia. Most Australian elections are run under full-preference preferential voting, where all candidates must be numbered in order of the preference of the...
, or OPV). Antony Green
Antony Green
Antony John Green is an Australian psephologist and commentator for the Australian Broadcasting Corporation.-Early years and background:...
notes that "The exhaustion rate has approached 80% in some seats....optional preferential voting almost always assists the party with the highest primary vote."
Voter confusion
"Voter confusion" takes place when a voter cannot discern who to vote for.| Criterion | What does that mean? | STV Australian Senate The Senate is the upper house of the bicameral Parliament of Australia, the lower house being the House of Representatives. Senators are popularly elected under a system of proportional representation. Senators are elected for a term that is usually six years; after a double dissolution, however,... |
AV Australian House of Representatives The House of Representatives is one of the two houses of the Parliament of Australia; it is the lower house; the upper house is the Senate. Members of Parliament serve for terms of approximately three years.... |
Notes |
|---|---|---|---|---|
| How-to-vote cards | "Are how-to-vote cards used?" | See below | ||
To cast a valid ballot, Australian voters must rank every candidate. Australian political parties use "how to vote" cards to encourage votes for their candidates. Without compulsory rankings, voters would have the option to stop ranking when indifferent to their remaining choices.
Invalid ballots
"Invalid ballots" are ballots that cannot be counted. The most recent rate of invalid ballots for two systems is as follows:| Criterion | What does that mean? | FPTP | AV | Notes |
|---|---|---|---|---|
| Invalid ballots rate | "What is the most recent percentage of votes that cannot be counted?" | 1.0% (overall), 0.28% (non-postal votes), 3.8% (postal votes) | 5.55% | See below |
"Invalid ballots" are called "informal ballots" in Australia (where voting is compulsory) and "spoilt ballots" in the United Kingdom (where voting is optional).
Voter participation
"Turnout" is the number of people who do vote compared with the number of people who can. The most recent turnouts for two systems is as follows:| Criterion | What does that mean? | FPTP | AV | Notes |
|---|---|---|---|---|
| Turnout rate | "What is the most recent percentage of people who can vote that do vote?" | 65.1% | 93.21% | See below |
Voting is compulsory in Australia and optional in the United Kingdom.
Risk of fraud in the United States
Fraudulent counting in the United States takes place when the count is interfered with.| Criterion | What does that mean? | FPTP | AV | Notes |
|---|---|---|---|---|
| Fraudulent counting in the USA | "Are elections fraudulent in the USA?" | See below | See below | See below for the discussion |
Most counties in the United States use voting machines to register and count their votes at the polling place. Although first choices can be counted at the polling place, AV ballots usually are counted in a central location in races without a first round majority winner. Changing the voting system by counting the vote centrally may increase the risk of fraud or may not increase the probability of fraud associated with such machine counts. FPTP need not be counted centrally.
Risk of fraud in Australia
Fraudulent counting in Australia takes place when the count is interfered with.| Criterion | What does that mean? | STV Australian Senate The Senate is the upper house of the bicameral Parliament of Australia, the lower house being the House of Representatives. Senators are popularly elected under a system of proportional representation. Senators are elected for a term that is usually six years; after a double dissolution, however,... |
AV Australian House of Representatives The House of Representatives is one of the two houses of the Parliament of Australia; it is the lower house; the upper house is the Senate. Members of Parliament serve for terms of approximately three years.... |
Notes |
|---|---|---|---|---|
| Fraudulent counting in Australia | "Are elections fraudulent in Australia" | See below for the discussion | ||
Australia (except for ACT
Australian Capital Territory
The Australian Capital Territory, often abbreviated ACT, is the capital territory of the Commonwealth of Australia and is the smallest self-governing internal territory...
) uses paper and pencils to vote and counts the votes by hand in a central location after unofficial tallies at the polling place. The fear of fraud is less.
Tactical voting
"Vote-splitting" occurs when voters split their votes between similar candidates, allowing a dissimilar candidate to win. One or more of the similar candidates may be characterised as a "spoiler" and the result as the "spoiler effect"."Tactical voting" occurs when a voter lists an "insincere preference" for a candidate due to the "spoiler effect". An "insincere preference" is when a voter deliberately gives a candidate a dishonest preference to prevent somebody winning (or another undesirable outcome).
| Criterion | What does that mean? | FPTP | AV | Notes |
|---|---|---|---|---|
| Is tactical voting possible? | "In theory, can people vote insincerely to prevent somebody winning?" | Tactical voting is theoretically possible in both FPTP and AV elections, see below | ||
| Does tactical voting occur in practice? | "In actual elections, do people vote insincerely to prevent somebody winning?" | Tactical voting occurs less in AV elections, see below | ||
| Does the spoiler effect occur? | "Can vote-splitting happen?" | See below | ||
| Does the spoiler effect occur when there are two major parties? | "Does vote-splitting happen when there are two major parties?" | See below | ||
Is tactical voting possible in theory?
The Gibbard–Satterthwaite theorem demonstrates that no voting system can be entirely immune from tactical voting unless it is dictatorial (there is only one person who is able to choose the winner) or incorporates an element of chance.IRV permits tactical voting if voters have complete and reliable information about the other voters' full preferences. The 2009 mayoral election
Burlington, Vermont mayoral election, 2009
The Burlington mayoral election of 2009 occurred on Tuesday, March 3, 2009. Burlington's mayoral race is partisan election that occurs every three years, and there are no term limits. The current mayor, Bob Kiss, has served since 2006. This marks the second mayoral election in Burlington using...
in Burlington, Vermont
Burlington, Vermont
Burlington is the largest city in the U.S. state of Vermont and the shire town of Chittenden County. Burlington lies south of the U.S.-Canadian border and some south of Montreal....
provides an example where tactical voting could have happened: most supporters of the candidate who came in second (and led the first-round) preferred the Condorcet
Condorcet method
A Condorcet method is any single-winner election method that meets the Condorcet criterion, which means the method always selects the Condorcet winner if such a candidate exists. The Condorcet winner is the candidate who would beat each of the other candidates in a run-off election.In modern...
winner (who IRV gave third place) over the IRV winner. If some of these voters had known that beforehand and insincerely raised their second-choice to first-choice, the Condorcet winner would have won the instant runoff, which these voters would have preferred.. In a three-party election where voters for both the left and right prefer the centrist candidate to stop the "enemy" candidate winning, those voters on the left and right who care more about defeating the "enemy" than electing their own candidate may cast a tactical first preference vote for the centrist candidate.
Does tactical voting occur in practice?
Under FPTP, voters have an incentive to vote insincerely for one of the two major candidates instead of their true favorite, because a vote for their true favorite is likely to be "wasted."In his book Collective Decisions and Voting Nicolaus Tideman
Nicolaus Tideman
T. Nicolaus Tideman is a Professor of Economics at Virginia Polytechnic Institute and State University. He received his Bachelor of Arts in economics and mathematics from Reed College in 1965 and his PhD in economics from the University of Chicago in 1969...
uses real-world voting data to analyze all proposed election methods in terms of resistance to tactical voting, and states on page 194 that "alternative vote [IRV] is quite resistant to strategy."
Does the spoiler effect occur?
IRV removes the spoiler effectSpoiler effect
The spoiler effect describes the effect a minor party candidate with little chance of winning has in a close election, when that candidate's presence in the election draws votes from a major candidate similar to them, thereby causing a candidate dissimilar to them to win the election...
when there are two major candidates and one or more minor candidates. In Australia, (a nation that uses IRV for its House of Representatives election) a smaller third party
National Party of Australia
The National Party of Australia is an Australian political party.Traditionally representing graziers, farmers and rural voters generally, it began as the The Country Party, but adopted the name The National Country Party in 1975, changed to The National Party of Australia in 1982. The party is...
co-exists with its coalition
Coalition (Australia)
The Coalition in Australian politics refers to a group of centre-right parties that has existed in the form of a coalition agreement since 1922...
partner
Liberal Party of Australia
The Liberal Party of Australia is an Australian political party.Founded a year after the 1943 federal election to replace the United Australia Party, the centre-right Liberal Party typically competes with the centre-left Australian Labor Party for political office...
, and functions without losing seats to other parties due to vote splitting. In Australia's national elections in November 2007, at least four candidates ran in every constituency, with an average of seven, and every constituency was won with an absolute majority of votes including several where results would have been different under plurality voting.
In the United States of America (a nation where states use FPTP for allocating Electoral College
Electoral college
An electoral college is a set of electors who are selected to elect a candidate to a particular office. Often these represent different organizations or entities, with each organization or entity represented by a particular number of electors or with votes weighted in a particular way...
votes in Presidential election), third party and independent candidates are often characterised as "spoilers" - such as in the 2000 Bush/Gore Presidential race where Ralph Nader
Ralph Nader
Ralph Nader is an American political activist, as well as an author, lecturer, and attorney. Areas of particular concern to Nader include consumer protection, humanitarianism, environmentalism, and democratic government....
was described as drawing support away from Al Gore
Al Gore
Albert Arnold "Al" Gore, Jr. served as the 45th Vice President of the United States , under President Bill Clinton. He was the Democratic Party's nominee for President in the 2000 U.S. presidential election....
, allowing George W. Bush
George W. Bush
George Walker Bush is an American politician who served as the 43rd President of the United States, from 2001 to 2009. Before that, he was the 46th Governor of Texas, having served from 1995 to 2000....
to win.
One person, one vote
"One person, one vote" (sometimes called "One man, one vote") is the principle that no voter be given greater weight in his or her vote over the vote of another voter.| Criterion | What does that mean? | FPTP | AV | Notes |
|---|---|---|---|---|
| One man, one vote | "Does every voter get the same number of votes and are they counted equally?" | See below | ||
In Ann Arbor, Michigan
Ann Arbor, Michigan
Ann Arbor is a city in the U.S. state of Michigan and the county seat of Washtenaw County. The 2010 census places the population at 113,934, making it the sixth largest city in Michigan. The Ann Arbor Metropolitan Statistical Area had a population of 344,791 as of 2010...
arguments over IRV in letters to newspapers included the belief that IRV "gives minority candidate voters two votes," because some voters' ballots may count for their first choice in the first round and a lesser choice in a later round. This argument was addressed and rejected by a Michigan court in 1975. In Stephenson v. the Ann Arbor Board of City Canvassers, the court held that "majority preferential voting" (as IRV was then known) was not a violation of one-man, one-vote.
Power of an individual vote
The "Voter Power Index" (VPI) for two systems is as follows:| Criterion | What does that mean? | FPTP | AV | Notes |
|---|---|---|---|---|
| Voter Power Index | "What is the power of an individual vote?" | 0.285 | 0.352 | See below |
The "Voter Power Index" (VPI) is a linear scale that measures how powerful an individual vote is. In the case above, 0 = perfectly powerless (a vote in a very safe constituency of very large size), and 1 = perfectly powerful (a vote in a very marginal constituency of average size).
Voter equality
"Voter equality" compares the least powerful fifth to the most powerful fifth of voters. Some results are below:| Criterion | What does that mean? | FPTP | AV | Notes |
|---|---|---|---|---|
| Voter equality | "How equal are voters in terms of their power?" | 4.8% (1/21) | 5.6% (1/18) | See below |
The "Voter equality" is the VPI for the least powerful fifth of voters divided by the VPI for the most powerful fifth of voters. In the case above, 0% = perfectly unequal (the least powerful fifth have no power) and 100% = perfectly equal (the least powerful fifth have the same power as the most powerful fifth).
Marginality
A constituency is "marginal" if there is a 1 in 5 chance or more that it will change hands in an election. A constituency that is not "marginal" is called "safe". How many constituencies would be safe in the United Kingdom (excluding Northern Ireland) in the 2010 election under different systems? Some results are below:| Criterion | What does that mean? | FPTP | AV | Notes |
|---|---|---|---|---|
| Very Marginal (GB) | What would the number of Very Marginal constituencies be under this system? | 81 | 125 | More than 1 in 3 chance of changing hands |
| Marginal (GB) | What would the number of Marginal constituencies be under this system? | 85 | 82 | Between 1 in 5 and 1 in 3 chance of changing hands |
| Fairly Safe (GB) | What would the number of Fairly Safe constituencies be under this system? | 135 | 154 | Between 1 in 10 and 1 in 5 chance of changing hands |
| Very Safe (GB) | What would the number of Very Safe constituencies be under this system? | 175 | 158 | Between 1 in 25 and 1 in 10 chance of changing hands |
| Ultra Safe (GB) | What would the number of Ultra Safe constituencies be under this system? | 156 | 113 | Less than 1 in 25 chance of changing hands |
The same study covered the United Kingdom (including Northern Ireland). The results are below:
| Criterion | What does that mean? | FPTP | AV | Notes |
|---|---|---|---|---|
| Very Marginal (UK) | What would the number of Very Marginal constituencies be under this system? | 82 | 126 | |
| Marginal (UK) | What would the number of Marginal constituencies be under this system? | 86 | 86 | |
| Fairly Safe (UK) | What would the number of Fairly Safe constituencies be under this system? | 142 | 159 | |
| Very Safe (UK) | What would the number of Very Safe constituencies be under this system? | 180 | 162 | |
| Ultra Safe (UK) | What would the number of Ultra Safe constituencies be under this system? | 160 | 117 | |
"Kicking the rascals out"
The "average churn rate" (characterised in the UK as "kicking the rascals out") for four systems since 1945 are as follows:| Criterion | What does that mean? | FPTP | AV Australian House of Representatives The House of Representatives is one of the two houses of the Parliament of Australia; it is the lower house; the upper house is the Senate. Members of Parliament serve for terms of approximately three years.... |
STV Dáil Éireann Dáil Éireann is the lower house, but principal chamber, of the Oireachtas , which also includes the President of Ireland and Seanad Éireann . It is directly elected at least once in every five years under the system of proportional representation by means of the single transferable vote... |
PRO | Notes |
|---|---|---|---|---|---|---|
| Average churn rate | "How easy is it to kick the rascals out?" | 17.3% | 19.0% | 17.4% | 21.0% | See below |
The "average churn rate" is a percentage that measures how easy it is to remove an elected member - the higher the number, the easier to "kick the rascals out". In the case above, 0% = impossible to remove any member in any election, 100% = every member loses every seat in every election.
Operating cost
On 2010-08-21 the 2010 Australian federal elections were held. The cost has not yet been released. On 2007-11-24 the 2007 Australian federal elections were held. The cost have been released. It does not give a quote for the cost of the House of RepresentativesAustralian House of Representatives
The House of Representatives is one of the two houses of the Parliament of Australia; it is the lower house; the upper house is the Senate. Members of Parliament serve for terms of approximately three years....
election (held under AV) separately from the cost of the Senate
Australian Senate
The Senate is the upper house of the bicameral Parliament of Australia, the lower house being the House of Representatives. Senators are popularly elected under a system of proportional representation. Senators are elected for a term that is usually six years; after a double dissolution, however,...
election (held under STV
Single transferable vote
The single transferable vote is a voting system designed to achieve proportional representation through preferential voting. Under STV, an elector's vote is initially allocated to his or her most preferred candidate, and then, after candidates have been either elected or eliminated, any surplus or...
) held on the same day. The costs are below.
On 2010-05-06 the 2010 UK general election was held. The cost has not yet been released but an estimate of the cost has. It does give a quote for the cost of the House of Commons election (held under FPTP) separately from the cost of the local elections (also held under FPTP) held on the same day. The costs are below.
| Voting system | FPTP | AV Australian House of Representatives The House of Representatives is one of the two houses of the Parliament of Australia; it is the lower house; the upper house is the Senate. Members of Parliament serve for terms of approximately three years.... /STV Australian Senate The Senate is the upper house of the bicameral Parliament of Australia, the lower house being the House of Representatives. Senators are popularly elected under a system of proportional representation. Senators are elected for a term that is usually six years; after a double dissolution, however,... |
Notes |
|---|---|---|---|
| Date of election | 2010-05-06 | 2007-11-24 | |
| Cost of election (excluding candidate funding) in local currency | £92,100,000 | $114,073,467 | |
| Local currency | GBP Pound sterling The pound sterling , commonly called the pound, is the official currency of the United Kingdom, its Crown Dependencies and the British Overseas Territories of South Georgia and the South Sandwich Islands, British Antarctic Territory and Tristan da Cunha. It is subdivided into 100 pence... |
AUD Australian dollar The Australian dollar is the currency of the Commonwealth of Australia, including Christmas Island, Cocos Islands, and Norfolk Island, as well as the independent Pacific Island states of Kiribati, Nauru and Tuvalu... |
|
| Exchange rate on the day of election (local->GBP Pound sterling The pound sterling , commonly called the pound, is the official currency of the United Kingdom, its Crown Dependencies and the British Overseas Territories of South Georgia and the South Sandwich Islands, British Antarctic Territory and Tristan da Cunha. It is subdivided into 100 pence... ) |
1 | 0.4251038342 | |
| Cost of election (excluding candidate funding) on the day of election in GBP Pound sterling The pound sterling , commonly called the pound, is the official currency of the United Kingdom, its Crown Dependencies and the British Overseas Territories of South Georgia and the South Sandwich Islands, British Antarctic Territory and Tristan da Cunha. It is subdivided into 100 pence... |
£92,100,000 | £48,493,068.20 | |
| Number of people who voted validly | 29,687,604 | 12,419,992 | |
| Cost of election (excluding candidate funding) on the day of election in GBP Pound sterling The pound sterling , commonly called the pound, is the official currency of the United Kingdom, its Crown Dependencies and the British Overseas Territories of South Georgia and the South Sandwich Islands, British Antarctic Territory and Tristan da Cunha. It is subdivided into 100 pence... per person who voted validly |
£3.10 | £3.90 |
Because it does not require two separate votes, AV costs less than two-round primary/general or general/runoff election systems.
Conversion cost in the USA
The "conversion cost in the USA" is the cost to convert from one voting system to another in the USA.| Criterion | What does that mean? | FPTP->AV | Notes |
|---|---|---|---|
| Conversion cost in the USA | "How much would it cost to convert to AV in the USA?" | See below | See below |
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."
The United States uses machines to register their votes and machines to count their votes. When voting takes place on machines relying on software, changing the voting system can lead to new costs. Pierce County, Washington
Pierce County, Washington
right|thumb|[[Tacoma, Washington|Tacoma]] - Seat of Pierce CountyPierce County is the second most populous county in the U.S. state of Washington. Formed out of Thurston County on December 22, 1852, by the legislature of Oregon Territory...
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. In 2009 the auditor [chief elections director of Washington counties] reported ongoing costs that were not necessarily balanced by the costs of eliminating runoffs for most county offices, as those elections may be needed for other offices not elected by IRV. Other jurisdictions have reported immediate cost savings.
Conversion cost in Australia
The "conversion cost in Australia" is the cost to convert from one voting system to another in Australia.| Criterion | What does that mean? | FPTP->AV | Notes |
|---|---|---|---|
| Conversion cost in Australia (AV) | "How much did it cost to convert to AV in Australia?" | See below | See below |
Australia (except for ACT
Australian Capital Territory
The Australian Capital Territory, often abbreviated ACT, is the capital territory of the Commonwealth of Australia and is the smallest self-governing internal territory...
) uses paper and pencils to vote and counts the votes by hand in a central location. The cost of running an election per capita is greater Australia, however, as AV involves more than one round.
Rules of Order
"Rules of Order" are rulebooks that recommend how parliamentary assemblies should be run. Their comparative assessment of voting systems are given below| Criterion | What does that mean? | Plurality (including FPTP) |
Preferential (including AV) |
Multiple-round (including Exhaustive ballot Exhaustive ballot The exhaustive ballot is a voting system used to elect a single winner. Under the exhaustive ballot the elector simply casts a single vote for his or her favorite candidate. However if no candidate is supported by an overall majority of votes then the candidate with the fewest votes is eliminated... and Two-round system Two-round system The two-round system is a voting system used to elect a single winner where the voter casts a single vote for their chosen candidate... ) |
Notes |
|---|---|---|---|---|---|
| Robert's Rules of Order Robert's Rules of Order Robert's Rules of Order is the short title of a book containing rules of order intended to be adopted as a parliamentary authority for use by a deliberative assembly written by Brig. Gen... |
"Which system does that rulebook recommend?" | That rulebook ranks plurality below preferential and multiple-round systems | That rulebook ranks preferential above plurality but below multiple-round systems | That rulebook ranks multiple-round systems above preferential and plurality | See below |
| The Standard Code of Parliamentary Procedure The Standard Code of Parliamentary Procedure The Standard Code of Parliamentary Procedure is a book of rules of order. It is the second most popular parliamentary authority in the United States after Robert's Rules of Order. It was first published in 1950... |
"Which system does that rulebook recommend?" | That rulebook ranks plurality below preferential and multiple-round systems | That rulebook ranks preferential above plurality but below multiple-round systems | That rulebook ranks multiple-round systems above preferential and plurality | See below |
| Riddick's Rules of Procedure Riddick's Rules of Procedure Riddick's Rules of Procedure is a parliamentary authority - a book explaining the parliamentary procedure, including the rules, ethics, and customs governing meetings and other operations of the United States Senate. It was written by Floyd M. Riddick and co-authored by Miriam Butcher... |
"Which system does that rulebook recommend?" | That rulebook ranks plurality below preferential and multiple-round systems | That rulebook ranks preferential above plurality but below multiple-round systems | That rulebook ranks multiple-round systems above preferential and plurality | See below |
The sequential elimination method used by IRV is described in Robert's Rules of Order
Robert's Rules of Order
Robert's Rules of Order is the short title of a book containing rules of order intended to be adopted as a parliamentary authority for use by a deliberative assembly written by Brig. Gen...
Newly Revised, 10th edition. as an example of "preferential voting
Preferential voting
Preferential voting is a type of ballot structure used in several electoral systems in which voters rank candidates in order of relative preference. For example, the voter may select their first choice as '1', their second preference a '2', and so on...
," 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." And then the instant runoff voting method is detailed.
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."
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
The Standard Code of Parliamentary Procedure
The Standard Code of Parliamentary Procedure is a book of rules of order. It is the second most popular parliamentary authority in the United States after Robert's Rules of Order. It was first published in 1950...
and Riddick's Rules of Procedure
Riddick's Rules of Procedure
Riddick's Rules of Procedure is a parliamentary authority - a book explaining the parliamentary procedure, including the rules, ethics, and customs governing meetings and other operations of the United States Senate. It was written by Floyd M. Riddick and co-authored by Miriam Butcher...
.
One-party dominance
"One-party dominance" is achieved when the opposition is so small that it cannot act as an opposition. How often does this happen? Some results are below:| Criterion | What does that mean? | FPTP | AV | STV Single transferable vote The single transferable vote is a voting system designed to achieve proportional representation through preferential voting. Under STV, an elector's vote is initially allocated to his or her most preferred candidate, and then, after candidates have been either elected or eliminated, any surplus or... |
PRO Party-list proportional representation Party-list proportional representation systems are a family of voting systems emphasizing proportional representation in elections in which multiple candidates are elected... |
AMS Additional Member System The Additional Member System is the term used in the United Kingdom for the mixed member proportional representation voting system used in Scotland, Wales and the London Assembly.... |
Notes |
|---|---|---|---|---|---|---|---|
| One-party dominance (90% plus) | "How often will the ruling party have 90% or more of the seats?" | 16.7% (4/24) | 25.0% (6/24) | 0% (0/24) | 0% (0/24) | 0% (0/24) | See below |
| One-party dominance (70%-90%) | "How often will the ruling party have between 70%-90% of the seats?" | 20.8% (5/24) | 12.5% (3/24) | 0% (0/24) | 8.3% (2/24) | 0% (0/24) | See below |
| One-party dominance (70% plus) | "How often will the ruling party have 70% or more of the seats?" | 37.5% (9/24) | 37.5% (9/24) | 0% (0/24) | 8.3% (2/24) | 0% (0/24) | See below |
If 90 per cent of council seats are held by a single party, opposition is effectively neutered. If 70 per cent of council seats are held by the majority party there will be some effective opposition but it can always be outvoted.
Conduct (ethnic campaigning)
"Ethnic campaigning" occurs when a candidate attacks another candidate's ethnicity to encourage the voter to vote against that candidate.| Criterion | What does that mean? | FPTP | AV | Notes |
|---|---|---|---|---|
| Ethnic conflict | "Does this system decrease ethnic conflict?" | See below | ||
Benjamin Reilly suggests instant runoff voting eases ethnic conflict in divided societies. This was a leading reason why Papua New Guinea
Papua New Guinea
Papua New Guinea , officially the Independent State of Papua New Guinea, is a country in Oceania, occupying the eastern half of the island of New Guinea and numerous offshore islands...
adopted instant runoff voting. The result in Fiji which adopted it for the same reason were not encouraging.
Conduct (negative campaigning)
"Negative campaigning" occurs when a candidate attacks another candidate to encourage the voter to vote against that candidate.| Criterion | What does that mean? | FPTP | AV | Notes |
|---|---|---|---|---|
| Negative campaigning Negative campaigning Negative campaigning, also known more colloquially as "mudslinging", is trying to win an advantage by referring to negative aspects of an opponent or of a policy rather than emphasizing one's own positive attributes or preferred policies... |
"Does this system decrease negative campaigning?" | See below | See below | |
John Russo, Oakland City Attorney, argued in the Oakland Tribune on July 24, 2006 that "Instant runoff voting is an antidote to the disease of negative campaigning. 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. Others state that there is a lack of evidence that such an effect occurs as often as suggested. Indeed, Lord Alexander's objections to the conclusions of the British Independent Commission on the Voting System's report cites the example of Australia saying "their politicians tend to be, if anything, more blunt and outspoken than our own."