Instant-runoff voting: Difference between revisions

 

Outside the US, IRV is known as the '''[[Alternative Vote]]''', '''[[preferential voting]]''', '''single-winner STV''', or the '''[[Thomas Hare|Hare]] System''', though there is room for confusion with some of these terms, since they can also refer to STV in general. In the US, IRV is also known as '''Ranked Choice Voting''' ('''RCV'''), a term preferred by election officials in San Francisco in 2004 because election results were not instant, and voters are responsible for ranking candidates.<ref name=":0">As described on a [https://web.archive.org/web/20040514072509/http://www.ci.sf.ca.us/site/election_page.asp?id=24269 City of San Francisco election page in 2004] "''Is 'ranked-choice voting' the same as 'instant runoff voting'? In San Francisco, ranked-choice voting is sometimes called 'instant run-off voting.' The Department of Elections generally uses the term ranked-choice voting, because it describes the voting method—voter are directed to rank their first, second and third choice candidates. The Department also uses the term ranked-choice voting because the word 'instant' might create an expectation that final results will be available immediately after the polls close on election night. But the term 'instant run-off' does not mean instantaneous reporting of results—the term means that there is no need for a separate run-off election.''"</ref>

 

Instant-Runoff Voting was invented around 1870 by American architect [[William Robert Ware]], who simply applied Hare's method to single-winner elections.<ref>{{Cite book|url=https://books.google.com/books?id=W7QRAAAAYAAJ&pg=PA192|title=Application of Mr. Hare's system of voting to the nomination of overseers of Harvard College.|last=Ware|first=William R.|date=1871|publisher=|year=|isbn=|location=|pages=|oclc=81791186|quote=It is equally efficient whether one candidate is to be chosen, or a dozen.}}</ref><ref>{{cite web|url=http://archive.fairvote.org/articles/reilly.pdf|title=The Global Spread of Preferential Voting: Australian Institutional Imperialism|author=Benjamin Reilly|publisher=FairVote.org|accessdate=17 April 2011}}</ref> Ware was not a mathematician, thus never subjected his election method to any rigorous analysis. He evidently based IRV on the single winner outcome of the [[Single Transferable Vote]] or STV developed in 1855 originally by [[Carl Andrae]] in [[Denmark]]. It was introduced into [[England]] in 1857 by the [[barrister]] [[Thomas Hare]], where it earned public praise from [[John Stuart Mill]], an English philosopher, member of parliament, and employee of the [[British East India Company|East India Company]].

 

IRV is used to elect the Australian House of Representatives, the lower houses of most of Australia's state parliaments, the President of Ireland, the Papua New Guinea National Parliament, and the Fijian House of Representatives. See below for a more detailed list.

 

== How IRV works ==

 

=== Voting ===

 

=== Counting the votes ===

Also consider batch elimination: if some batch of candidates can be eliminated that collectively have fewer votes than some other candidate. Example vote totals: 30 A 19 B 5 C 4 D 6 E. Because C, D, and E's collective 15 votes can't overtake B's 19 votes, all 3 can be eliminated at once without changing the result.

 

 

== Where IRV is used ==

===Logistical issues===

 

 

With IRV, each time a candidate is dropped, the ballots assigned to them must be re-examined to determine which remaining candidate to assign them to. Repeated several times, this can be time-consuming. If there is a candidate X who got more votes than all of the candidates who got less than X put together, then all of these candidates who lost to X can be dropped simultaneously without affecting the final outcome, which can speed up counting.

In normal [[runoff voting]], D and E are the two candidates with the most votes, preventing the majority's preferred candidates from entering the runoff. In FPTP, D has the most votes. But with IRV, first C is eliminated, and then E, and then B, resulting in A having 51 votes and winning. Note that though the 49 voter-minority preferred B to A, B didn't win; this is an example of IRV ignoring voter preferences in a way that can lead to some majorities (when looking at [[Head-to-head matchup|head-to-head matchups]]) having less power. However, the majority still got a better result than it would've had in some other methods.

 

 

IRV is equivalent to [[runoff voting]] (supposing no change in preferences) when there are 3 or fewer candidates. This is used to argue both for and against it; advocates claim it is cheaper and easier for the voters to vote once, while opponents argue that a delayed runoff actually gives voters a second look into the candidates in the runoff, potentially improving the quality of their decision-making, and that because ranking candidates is harder than picking one candidate, that runoff voting is actually easier for voters. Note that though IRV is called instant runoff, this is more because it elects a candidate who could win or tie a runoff ([[pairwise beat]] or tie) against at least one other candidate, rather than because it is equivalent to runoff voting in all cases.

 

In 1993, the Center for Voting and Democracy (now known as "[[FairVote]]") published their first annual report. In that report, they referred to the system as "preference voting",<ref>https://web.archive.org/web/19990507180316/http://www.fairvote.org/cvd_reports/1993/introduction.html</ref> which included the following caveat:<blockquote>''A Note on Terminology: Reflecting the range of contributors, this report has some inconsistencies in terminology to describe different voting systems. In addition, what many call the "single transferable vote" here is termed "preference voting" in order to focus on the voting process rather than the ballot count.''</blockquote>In 1997, FairVote began referring to preferential voting as "Instant Runoff voting".<ref>[https://www.csmonitor.com/1997/0721/072197.opin.opin.1.html &quot;Fuller, Fairer Elections? How?&quot;]. ''Christian Science Monitor''. 1997-07-21. [https://en.wikipedia.org/wiki/International_Standard_Serial_Number ISSN] [https://www.worldcat.org/issn/0882-7729 0882-7729]<span class="reference-accessdate">. Retrieved <span class="nowrap">2019-12-14</span></span>.</ref><ref>From [https://web.archive.org/web/19990427031915/http://www.fairvote.org/email_archives/070298.htm the 1998 newsletter]: "Note that the transferable ballot can be used as a proportional representation system in multi-seat districts (what we call "choice voting") and in one-winner elections (what we call "instant runoff voting")."</ref> However, the city of San Francisco preferred the term "ranked-choice voting", which was used as early as 1999.<ref>http://archive.fairvote.org/library/statutes/irv_stat_lang.htm San Francisco Charter Amendment, introduced October 1999 "SEC. 13.102. RANKED-CHOICE BALLOTS"</ref><ref>Instant Runoff Voting Charter Amendment for San Francisco passed on March 5, 2002, "''to provide for the election of the Mayor, Sheriff, District Attorney, City Attorney, Treasurer, Assessor-Recorder, Public Defender, and members of the Board of Supervisors using a ranked-choice, or “instant run-off,” ballot, to require that City voting systems be compatible with a ranked-choice ballot system, and setting a date and conditions for implementation.''"</ref> By 2004, San Francisco was careful to explain that the method codified as "ranked choice voting" was the same as "instant runoff voting.<ref name=":0" /> Because organizations in Arizona borrowed San Francisco's language, many used "ranked choice" as the preferred wording, which [[FairVote]] accommodated as early as 2006.<ref>"[https://web.archive.org/web/20060927205517/http://www.fairvote.org/rcv/ FairVote and the LWV-Arizona Support Ranked Choice Voting]" Dr. Barbara Klein and Rob Richie</ref> [[FairVote]] didn't appear to publicly deprecate the term "instant runoff voting" until 2013,<ref>The [https://web.archive.org/web/20130729141521/http://www.fairvote.org/ July 2013 homepage of fairvote.org] was the first to refer to "ranked choice voting" as a preferred term to "instant-runoff"</ref> but now appears to prefer "ranked choice voting" to describe the method.

 

==See also==

*[[Table of voting systems by nation]]

*[[Bottom-Two-Runoff IRV]] - a variant that meets the Condorcet criterion

 

== References ==

==External links==

* Pro/advocacy positions

** [http://instantrunoff.com instant runoff]

** [http://www.firv.org Ferndale for Instant Runoff Voting]

* Examples

** [http://www.mnip.org/caucusresults.htm Minnesota Independence Party 2004, IRV poll for U.S. President.]

** [http://www.aec.gov.au/ Australian Electoral Commission]

*Further Explanation

** [http://anewprogressiveamerica.blogspot.com/2004/11/what-is-instant-runoff-voting.html What is Instant Runoff Voting?]

 

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[[Category:Plurality-runoff voting methods]]

[[Category:Sequential loser-elimination methods]]