Bottom-Two-Runoff IRV: Difference between revisions

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BTR-IRV was originally proposed by [[User:Legrand|Rob LeGrand]] in 2006.<ref name=":0">[https://election-methods.electorama.narkive.com/LKfc52OI/an-example-of-btr-stv#post4 election-methods mailing list: An example of BTR-STV]</ref><ref>[https://www.mail-archive.com/election-methods@electorama.com/msg01311.html <nowiki>[EM] DH3 - error by me - should prefer BTR-IRV to Schulze beatpaths?</nowiki>]</ref> It was conceived as a modification to standard [[Instant-runoff voting|Instant-runoff voting (IRV)]] which ensures the runoff doesn't ever eliminate a Condorcet Winner (and in fact, never eliminates all candidates in the [[Smith set]], since a Smith set member can never be eliminated in a runoff against a non-Smith set member). Thus, the method passes the [[Condorcet Criterion]] and the [[Smith criterion]], ensuring it functions as a [[Condorcet method]].
BTR-IRV was originally proposed by [[User:Legrand|Rob LeGrand]] in 2006.<ref name=":0">[https://election-methods.electorama.narkive.com/LKfc52OI/an-example-of-btr-stv#post4 election-methods mailing list: An example of BTR-STV]</ref><ref>[https://www.mail-archive.com/election-methods@electorama.com/msg01311.html <nowiki>[EM] DH3 - error by me - should prefer BTR-IRV to Schulze beatpaths?</nowiki>]</ref> It was conceived as a modification to standard [[Instant-runoff voting|Instant-runoff voting (IRV)]] which ensures the runoff doesn't ever eliminate a Condorcet Winner (and in fact, never eliminates all candidates in the [[Smith set]], since a Smith set member can never be eliminated in a runoff against a non-Smith set member). Thus, the method passes the [[Condorcet Criterion]] and the [[Smith criterion]], ensuring it functions as a [[Condorcet method]].

A benefit of BTR-IRV is that first choices are honored in the elimination process, so that a polarizing candidate can survive to later rounds until they have a single opponent who they can be individually compared to. This attribute and ease of explaining the system makes it less prone to claims of fraud than other systems for resolving the [[Condorcet paradox]].


This system is a form of [[Single transferable vote|single transferable vote (STV)]], and may be referred to by the more general name '''BTR-STV''', thought the multi-winner variant was not originally recommended by LeGrand.<ref name=":0" />
This system is a form of [[Single transferable vote|single transferable vote (STV)]], and may be referred to by the more general name '''BTR-STV''', thought the multi-winner variant was not originally recommended by LeGrand.<ref name=":0" />