[EM] Defeat strength, Winning Votes vs. Margins, what to do with equally-ranks on ballot?

Kevin Venzke stepjak at yahoo.fr
Mon May 20 18:48:45 PDT 2019

 Hi Robert,
In a WV method you can't trace beatpaths through a loss. So if A defeats B you can only trace from A to B, and the strength of the defeat is equal to the number of voters who preferred A>B. (If you added half a vote to A in the case of an equal ranking between A and B, this gives the same effect as margins, assuming you applied this rule everywhere.)
Normally these methods do not show a difference based on whether an equal ranking was explicit, vs. implied via truncation. I would say this is mostly because explicit vs. implicit ranking isn't really native/inherent to the idea of Condorcet. But I'd suggest also because a distinction in treatment doesn't help the voter. A "half vote" treatment turns equal ranking into a "neither here nor there" strategy, where ranking your favorite candidates equal-top is prima facie not optimal regardless of your priorities.

    Le lundi 20 mai 2019 à 16:06:32 UTC−5, robert bristow-johnson <rbj at audioimagination.com> a écrit :  

So this would be about Tideman Ranked-Pairs, or Schulze, or some other Condorcet-compliant method.

It doesn't make much difference if the measure of Defeat Strength is Margins (supporting votes minus opposing votes), but what if Winning Votes is the measure of Defeat Strengthin either RP or Schulze?  How should a pair of candidates that are equally-ranked on a ballot be counted?  Do you count it (as a winning vote) for *both* candidates?  For neither candidate?  (I dislike the idea of a half-vote for both candidates.  And I hate the idea of notallowing equal-ranking in a Condorcet RCV election.)

What is the right way to do this?  It seems the most consistent might be to count an equally-ranked votes for **neither** candidate, since we consider unranked candidates as tied for last place on the ballot, and we would count those asvotes.

But what do you guys think?  If we allow for equal-ranking in a Condorcet-compliant RCV, how do we deal with it in terms of vote totals?


r b-j                         rbj at audioimagination.com

"Imagination is more important than knowledge."



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