Pairwise counting: Difference between revisions

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(SLEM methods usually satisfy Condorcet-loser too.)
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'''Pairwise counting''' is the process of considering a set of items, comparing one pair of items at a time, and for each pair counting the comparison results. In the context of voting theory, it involves comparing pairs of candidates or winner sets (usually using majority rule) to determine the winner and loser of the [[Pairwise matchup|pairwise matchup]]. This is done by looking at voters' (usually [[Ranked ballot|ranked]] or [[Rated ballot|rated]]) ballots to count, for each pair of candidates, which one they indicated a preference for, if they did. The [[pairwise preference]] article discusses how pairwise comparison information can be used.
 
Most, but not all, election methods that meet the [[Condorcet criterion]] use pairwise counting.<ref group="nb">[[Nanson'sThe method|Nanson]]most meetscommon theexceptions [[Condorcetare criterion]]hybrid and(e.g. [[Instant-runoffSmith//X) voting]]methods meets the [[Condorcetand sequential-loser-elimination criterion]]methods.</ref> See the [[Pairwise counting#Condorcet|Condorcet section]] for more information on the use of pairwise counting in [[Condorcet methods]].
 
== Procedure ==