Difference between revisions of "Instant-runoff voting"

From Ballotpedia
Jump to: navigation, search
m
 
Line 1: Line 1:
{{tnr}}'''Instant-runoff voting''' (or '''IRV''') is a voting system used for single winner elections in which voters rank candidates in order of preference.  
+
{{tnr}}'''Instant-runoff voting''' (or '''IRV''') is a voting system that allows voters to rank candidates in order of preference.<ref name="fv">[http://www.fairvote.org/reforms/instant-runoff-voting/how-instant-runoff-voting-works/ ''FairVote'', "How Instant Runoff Voting Works," accessed April 29, 2014]</ref> Instead, IRV does not allow a candidate to win a race without the majority of the votes cast by the electorate.<ref name="cc">[http://www.commoncause.org/site/pp.asp?c=dkLNK1MQIwG&b=4849119 ''Common Cause'', "Instant Runoff Voting," accessed April 29, 2014]</ref><ref name="hawaii"/><ref name="pr">[http://www.princeton.edu/~achaney/tmve/wiki100k/docs/Instant-runoff_voting.html ''Princeton.edu'', "Instant-Runoff Voting"]</ref>
  
In an IRV election, if no candidate receives an overall majority of first preferences, the candidates with fewest votes are eliminated one by one, and their votes transferred according to their second and third preferences (and so on) and all votes retallied, until one candidate achieves a majority. The term 'instant runoff voting' is used because this process resembles a series of runoff elections.
+
The term 'instant runoff voting' is used because this process resembles a series of runoff elections but without the voter returning weeks later to vote in a runoff election.<ref name="hawaii">[http://www.hawaii.edu/uhmfs/documents/resolutions/Instant-Runoff%20Voting.pdf ''Hawaii.edu'', "Instant-Runoff Voting," accessed April 29, 2014]</ref>
  
At a national level IRV is used to elect the Australian House of Representatives, the President of Ireland, the national parliament of Papua New Guinea and the Fijian House of Representatives. In the United States, it has been adopted in nine local jurisdictions, including three large population cities and counties during the 2006 United States general elections. In the United Kingdom, a form of IRV is used to elect the mayor of London.
+
In the United States, especially in [[California]], IRV is called "Ranked Choice Voting" or "RCV."<ref>[http://californiawatch.org/dailyreport/low-income-voters-struggled-ranked-choice-voting-7840 ''California Watch'', "Low-income voters struggled with ranked-choice voting," accessed January 5, 2011]</ref>
  
==Terminology==
+
==Process==
[[Image:IRVballot.jpg|right|IRV example ballot]]
+
[[Image:IRVballot.jpg|right|IRV example ballot|link=Instant-runoff voting]]
Instant runoff voting has been called a number of other names. In the United Kingdom, it is known as the '''Alternative Vote''' ('''AV'''), or as the '''Alternative Transferrable Vote''' ('''ATV'''). In Australia, the generic term '''preferential voting''' is used (though all voting systems aim to discover preference, simple majority voting does not allow expressions of preference through ranking, as does IRV). When used in Canada in the past it was known as the '''preferential ballot'''. It is also sometimes known in the United States as '''ranked choice voting'''.
+
In an IRV system, voters rank candidates in order of preference.If no candidate receives an overall majority of first preferences, the candidates with fewest votes are eliminated one by one and their votes transferred according to their second and third preferences (and so on) and then all votes retallied, until one candidate achieves a majority.<ref name="fv"/><ref name="cc"/><ref name="hawaii"/><ref name="pr"/>
  
When the single transferable vote (STV) system is applied to a single-winner election it becomes the same as IRV. For this reason IRV is sometimes considered to be merely a special form of STV. However, because STV was designed for multi-seat constituencies, many scholars consider it to be a separate system from IRV, and that is the convention followed in this article.
+
Under the most common [[ballot]] layout, the voter places a "1" beside their most preferred candidate, a "2" beside their second most preferred and so on. In the ballot paper shown to the right of this page, the preferences of the voter are as follows:
 
+
IRV is usually known simply as "STV" in New Zealand and Ireland, although the term the 'Alternative Vote' is also sometimes used in those countries. IRV is sometimes referred to as the '''Hare system''', after Thomas Hare, one of the inventors of STV. It has also been referred to as '''Ware's method''', after its own inventor, William Robert Ware. Writers differ as to whether or not they treat ''instant runoff voting'' as a proper noun.
+
 
+
In the United States, especially in [[California]], IRV is called "Ranked Choice Voting."<ref>[http://californiawatch.org/dailyreport/low-income-voters-struggled-ranked-choice-voting-7840 ''California Watch'', "Low-income voters struggled with ranked-choice voting," January 5, 2011]</ref>
+
 
+
==Voting==
+
In IRV the voter ranks the list of candidates in order of preference. Under the most common [[ballot]] layout, the voter places a '1' beside their most preferred candidate, a '2' beside their second most preferred, and so forth. In the ballot paper shown at the top-right of this page the preferences of the voter are as follows:
+
  
 
#Joe Bobb
 
#Joe Bobb
Line 22: Line 15:
 
#Righty Fahr
 
#Righty Fahr
  
Each voter may be said to cast only one vote but, during the process of counting votes, his vote may be 'transferred' from one candidate to another.
+
Each voter may only cast one vote, but during the process of counting votes, a votes may be 'transferred' from one candidate to another.<ref name="fv"/>
  
==Counting the votes==
+
===Counting===
 +
Ballots are initially sorted according to their expressed first preferences, and if no candidate achieves an overall majority of "first" preferences, then the candidate with the "fewest" first preferences is eliminated. That candidate's votes are then recounted and are distributed to the remaining candidates according to the "second" preferences expressed on each ballot paper. If there is still not an overall majority of votes, then this process is continually repeated.<ref name="fv"/><ref name="cc"/><ref name="hawaii"/><ref name="pr"/> 
  
In an IRV election, every voter has one vote -- at least in the sense that each voter uses only one ballot -- but can express more than one preference. Ballots are initially sorted according to their expressed first preferences. If no candidate achieves an [[simple majority|overall majority]] of first preferences (more than half of the total vote) then the candidate with the fewest first preferences is eliminated. That candidate's votes are recounted and are distributed to the remaining candidates according to the ''second'' preferences expressed by each ballot paper. If there is still no candidate with an overall majority of votes then the candidate with the fewest votes in this round of counting is eliminated and his or her votes transferred in the same way, according to the ''second or third'' preferences expressed by each ballot paper. This process of counting and eliminating continues until a candidate has obtained an overall majority of votes in the final round of counting.
+
==See also==
 
+
{{td}}
Once candidates are eliminated or 'excluded', no votes can be transferred to them. Therefore if a ballot paper being recounted expresses a preference for a candidate who has already been excluded, the next 'live' preference on the ballot is used instead.
+
* [[Voting]]
 
+
* [[Voting Rights Act]]
IRV with batch elimination descibes a two-round method of IRV where if no candidate receives a majority of the first round preferences, all candidates but the top two are eliminated and all ballots are counted for whichever of the two runoff candidates is ranked first on that ballot.
+
* [[National Voter Registration Act]]
 +
* [[Help America Vote Act (HAVA) of 2002]]
 +
* [[Federal Election Commission]]
 +
* [[Election Assistance Commission]]
 +
* [[State by State Voter ID Laws]]
 +
* [[Electoral College]]
 +
* [[Voter registration]]
 +
* [[Vote fraud]]
 +
* [[:Category:Terms and definitions|Terms and definitions]]
  
 
==External links==
 
==External links==
 +
{{submit a link}}
 +
* [http://www.fairvote.org FairVote]
 +
* [http://fairvote.org/?page=5  FairVote's Right to Vote Initiative]
 +
* [http://fairvote.org/?page=19  FairVote's IRV America]
  
* [http://www.fairvote.org  FairVote]
+
==Additional reading==
* [http://fairvote.org/?page=5  Right to Vote Initiative]
+
* [http://www.newamerica.net/files/NAF_10big_Ideas_9.pdf ''New America.net'', "Instant Runoff Voting"]
* [http://fairvote.org/?page=19  IRV America]
+
* [http://www.hawaii.edu/uhmfs/documents/resolutions/Instant-Runoff%20Voting.pdf ''Hawaii.edu'', "Instant-Runoff Voting"]
* [http://fairvote.org/?page=37  Program For Representative Government]
+
* [http://www.princeton.edu/~achaney/tmve/wiki100k/docs/Instant-runoff_voting.html ''Princeton.edu'', "Instant-Runoff Voting"]
* [http://fairvote.org/presidential-nominations-reform  Presidential Elections Reform Program]
+
* [http://www.newrepublic.com/article/78043/instant-runoff-voting-elections-florida-2000 ''New Republic'', "Rank the Vote"]
* [http://fairvote.org/?page=34  Democracy SoS]
+
* [https://www.mtholyoke.edu/acad/polit/damy/articles/irv.htm ''Mount Holyoke.edu'', "Instant Runoff Voting: No Substitute for Proportional Representation"]
 
+
---
+
Portions of this article were adapted from [http://en.wikipedia.org/wiki/Instant-runoff_voting the article about Instant-runoff voting on Wikipedia], the free encyclopedia. Wikipedia's Copyright Notice can be found [http://en.wikipedia.org/wiki/Wikipedia:Copyrights here].
+
  
 
==References==
 
==References==
 
{{reflist}}
 
{{reflist}}
{{election update|Month=April 29, 2014|Reason=Page needs extensive updates}}
+
 
 
[[Category:Terms and definitions]]
 
[[Category:Terms and definitions]]

Latest revision as of 17:15, 30 April 2014

Instant-runoff voting (or IRV) is a voting system that allows voters to rank candidates in order of preference.[1] Instead, IRV does not allow a candidate to win a race without the majority of the votes cast by the electorate.[2][3][4]

The term 'instant runoff voting' is used because this process resembles a series of runoff elections but without the voter returning weeks later to vote in a runoff election.[3]

In the United States, especially in California, IRV is called "Ranked Choice Voting" or "RCV."[5]

Process

IRV example ballot

In an IRV system, voters rank candidates in order of preference.If no candidate receives an overall majority of first preferences, the candidates with fewest votes are eliminated one by one and their votes transferred according to their second and third preferences (and so on) and then all votes retallied, until one candidate achieves a majority.[1][2][3][4]

Under the most common ballot layout, the voter places a "1" beside their most preferred candidate, a "2" beside their second most preferred and so on. In the ballot paper shown to the right of this page, the preferences of the voter are as follows:

  1. Joe Bobb
  2. Darryl Zero
  3. Righty Fahr

Each voter may only cast one vote, but during the process of counting votes, a votes may be 'transferred' from one candidate to another.[1]

Counting

Ballots are initially sorted according to their expressed first preferences, and if no candidate achieves an overall majority of "first" preferences, then the candidate with the "fewest" first preferences is eliminated. That candidate's votes are then recounted and are distributed to the remaining candidates according to the "second" preferences expressed on each ballot paper. If there is still not an overall majority of votes, then this process is continually repeated.[1][2][3][4]

See also

Ballotpedia:Index of Terms

External links

BallotpediaAvatar bigger.png
Suggest a link

Additional reading

References