[EM] margins vs wv

[MIKE OSSIPOFF]

Doug wrote:

I can point him to resources on range voting, but I don't know where the wv 
v.
margins debate is encapsulated.

I reply:

It's been such a wordy debate that it's probably never been
put together into 2 messages.

A margins advocate could say that he doesn't consider the majority
defensive strategy criteria important, but they measure for the
standards of majority rule and getting rid of the lesser-of-2-evils
problem. The wv methods are the ones that do well by the majority
defensive strategy criteria. The wv versions of Ranked-Pairs and
BeatpathWinner/CSSD meet all of them.

Aside from whether you like those particular criteria, it can't really be 
denied that margins is the big
violator of majority rule, and is the method that makes greater strategic 
demands on voters who want to protect majority rule, or who want to protect 
the win of a CW.

It was shown here that, with margins methods, there are plausible
ordinary situations in which the only Nash equilibria are ones in which
defensive order-reversal is used.

We probably agree that it's undesirable to have to drop a defeat,
since each pairwise defeat represents a public vote about the
relative merit of 2 candidates. Dropping a defeat overrules all the
voters who won that public vote. So we'd like to at least overrule
as few as possible.

Margins advocates would answer that not dropping a defeat overrules
the voters who voted agains that defeat. Wrong. Those voters were
overruled by the result of the public vote between those candidates.
Not dropping a defeat that the public enacted doesn't overrule anyone.

For that reason winning-votes (wv) is the more democratic class of
methods, when it comes to honoring pairwise votes and expressed
public wishes.

Margins advocates say that they like symmetry, and that margins
is more symmetrical. But the situations isn't symmmetrical--If
Smith beats Jones pairwise, there's an asymmetry between the Smith>Jones 
voters and the Jones>Smith voters: The Jones>Smith voters
lost.

Mike Ossipoff



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