Minimax Condorcet method: Difference between revisions
Rewrote the defeat-dropper note to clarify how they fail DMTBR.
m (RobLa moved page Minmax Condorcet method to Minimax Condorcet method: Oops, I left out one of "i"s from "Minimax") |
(Rewrote the defeat-dropper note to clarify how they fail DMTBR.) |
||
(8 intermediate revisions by 3 users not shown) | |||
Line 1:
{{Wikipedia|Minimax Condorcet method}}
In [[voting system]]s, the '''
Minimax selects as the winner the candidate whose greatest pairwise defeat is smaller than the greatest pairwise defeat of any other candidate: or, put another way, "the only candidate whose support never drops below [N] percent" in any pairwise contest.<ref>The introduction to this article was initially copied from https://en.wikipedia.org/w/index.php?title=Minimax_Condorcet_method&oldid=1156877070</ref>
== Variants ==
'''Minmax''' or Minimax method, also referred to as the '''Simpson-Kramer method''',<ref name="Caplin" /> is the name of a class of election methods based on electing the candidate with the most consistently high performance in pairwise contests with other candidates. It is sometimes also called the '''least reversal''' or '''successive reversal''' method,<ref name="Green-Armytage" /> although this term is ambiguous.
'''Minmax(winning votes)''' elects the candidate whose greatest pairwise loss to another candidate is the least, when the strength of a pairwise loss is measured as the number of voters who voted for the winning side.
Line 47 ⟶ 53:
MMPO has been criticized for its counter-intuitive behavior on some elections.<ref>{{cite web|url=http://lists.electorama.com/pipermail/election-methods-electorama.com/2016-September/000523.html|title=Re: MMPO objections (hopefully better posted)|website=Election-methods mailing list archives|date=2016-09-21|last=Benham|first=C.}}</ref> Given this election (called the "bad-example" on EM):
* x: '''A'''>B=C
* 1: '''A=C'''>B
* 1: '''B=C'''>A
* x: '''B'''>A=C
MMPO elects C even if x is made arbitrarily large (say, 3.95 billion voters). This is a [[Plurality criterion|Plurality]] failure.
== Notes ==
Line 59 ⟶ 65:
This contrasts with [[Schulze]], which alternates between eliminating all candidates not in the [[Schwartz set]] and dropping defeats.
All [[:Category:Defeat-dropping Condorcet methods|defeat-dropping Condorcet methods]] become equivalent to Minimax
Since the defeat-droppers are equivalent to
== References ==
Line 76 ⟶ 74:
[[Category:Single-winner voting methods]]
[[Category:Ranked voting methods]]
[[Category:Condorcet methods]]
[[Category:Monotonic electoral systems]]
|