[EM] wv & margins definitions & difference

[MIKE OSSIPOFF]

In reply to the question about the difference between winning-votes
and margins, it's as Forest said: The difference occurs when
not everyone ranks all of the candidates. Truncation is common
in rank elections, and will always happen in public elections.

Say A beats B. Winning votes refers to the number of voters who
rank A over B. Margins refers to the number ranking A over B,
minus the number who rank B over A.

There are very important differences in strategy properties of the
methods using those 2 defeat-measures. The website
http://www.electionmethods.org lists some criteria, at its
technical evaluation page. All the criteria for which Condorcet is
listed as complying are criteria that BeatpathWinner(wv),
Cloneproof SSD, Plain Condorcet(wv), and Ranked-Pairs(wv) comply with.
The margins methods fail all of those criteria.

In addition, the margins methods are "falsifying", as I defined that
term here. With those methods, there are situations in which the
only equilibria are ones in which defensive order-reversal is used.

Mike Ossipoff


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