Wednesday, 17 July 2013

Instant-Runoff Voting better than First Past the Post

Instant runoff voting is used to elect members of the Australian House of Representatives and most Australian State Governments. However many people, especially outside of Australia do not know what Instant runoff voting is, this post will try to give a clear and simple explanation. Also you will see that it is a better system than the general voting systems (normally defined as First Past the Post) as it produces winners that a large number of people agree on.

As most of you should know, first-past-the-post election is one that is won by the candidate with more votes than any other(s). It is a common, but not universal, feature of electoral systems with single-member legislative districts, and generally results over time with a two-party competition.

Instant-runoff voting is an electoral system used to elect a single winner from a field of more than two candidates. It is a preferential voting system in which voters rank the candidates in order of preference rather than voting for a single candidate.
Ballots are initially distributed based on each elector's first preference. If a candidate secures more than half of votes cast, that candidate wins. Otherwise, the candidate with the fewest votes is eliminated. Ballots assigned to eliminated candidates are recounted and assigned to one of the remaining candidates based on the next preference on each ballot. This process continues until one candidate wins by obtaining more than half the votes.
Instant-runoff voting has the effect of avoiding split votes and the need for electors to vote "strategically" for candidates who are not their first choice. For example, suppose here are two conservative candidates A & B, and a liberal candidate C, with raw popularity of 35%, 25% and 40% respectively. In a Plurality voting system, candidate C may win with 40% of the votes even though most electors prefer A or B. Alternatively, a conservative elector who likes B may decide to vote for A instead in order to prevent C from being elected. With Instant-runoff voting , the elector can allocate their preferences B, A, C and then A will win despite the split vote in first choices.

Spoiler Effect

Although this system also faces some inefficiencies it is preferable as it eliminates spoiler effect .The spoiler effect is where two or more politically similar candidates divide the vote for the more popular end of the political spectrum. That is, each receives fewer votes than a single opponent on the unpopular end of the spectrum who is disliked by the majority of voters but who wins from the advantage that, on that unpopular side, he or she is unopposed.
Proponents of Instant runoff voting note that by reducing the spoiler effect, Instant runoff voting makes it safe to vote honestly for marginal parties, and so discourages tactical voting: under a plurality system, voters who sympathize most strongly with a marginal candidate are strongly encouraged to instead vote for a more popular candidate who shares some of the same principles, since that candidate has a much greater chance of being elected and a vote for the fringe candidate is largely wasted.
An Instant runoff voting system reduces this problem, since the voter can rank the marginal candidate first and the mainstream candidate second; in the likely event that the fringe candidate is eliminated, the vote is not wasted but is transferred to the second preference. However, in the event that the fringe candidate is not eliminated immediately, there is an increased chance for the mainstream candidate to lose, especially when multiple fringe candidates are running. If that happens, the opposing mainstream candidate has a much easier path to victory. As a result, voting honestly for a fringe candidate is unlikely to benefit the voter, and may backfire.

For an animated explanation please see the video below:


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Blog Editor and Owner: Luis Aparicio Fernandes (or Mikey) is a Business Expert and a Traveler based in Sydney, Australia. He is a member of The International Honor Society Beta Gamma Sigma due to his achievements in business. You can follow Luis on Google+, and LinkedIn.