[EM] Ordering defeats in Minimax

[Kevin Venzke]

Hi Juho,

De : Juho Laatu <juho.laatu at gmail.com>
À : Election Methods <election-methods at lists.electorama.com> 
Envoyé le : Jeudi 4 mai 2017 17h02
Objet : Re: [EM] Ordering defeats in Minimax

>Also this mail is a late rely. This time I had some additional problems since >I didn't receive this mail in my unbox at all. I found it in the electorama >mail archives. The mail traffic between electorama and me doesn't always work>perfectly.
Ok, I will be sure to copy you. I don't receive all the traffic either.
>I already answered Kristofer's question once, but I was maybe not as clear as>I should have been. I agree that Plurality can be classified as a criterion>that is intended to be a "natural behaviour" criterion. I used term>"heuristic", that os close to "intended to be a natural behaviour". Plurality>is however often linked with winning votes, that I consider to be a very>"strategic behaviour" related comparison method.
Well, Plurality is "linked" to WV only because it creates a contrast with margins. If you were comparing margins to IRV or to Bucklin one would stillbring up Plurality.
>>Sure, I would rather criticize how margins addresses this than the fact>>that it tries to address it. IRV does this, for instance: You can rank the>>worse frontrunner in a sincere way and you know that it won't hurt you. In>>margins we "want" you to rank the worse frontrunner, but it's not expected>>to be of any use to you, and it can hurt the better frontrunner by making>>"worse" look like your compromise choice.>>Yes, but what is the probability of hurting one's targets by ranking>numerous candidates in a Condorcet election with a bunch of potential winners>and few additional candidates that are unlikely to win? And what are the>benefits of ranking all the potential winners?
It's not whether they are ranked (margins will essentially force me to rankthem, I think), it's whether I decide to rank them sincerely. I think thespecific questions the voter might ask themselves are fairly clear.
Margins gives me the most heartburn when I consider how to rank the worstof the potential winners relative to the "additional" candidates who are"unlikely" to win and who may well be unqualified to hold the office. As Iwrote above, there is no realistic gain for me to indicate that the worstfrontrunner is better than anybody, and there could be a cost. The odds ofthe latter? I don't know, but I'm comparing "something" to a 0% chance, and that could certainly allow me to make a decision.
(It's possible that people like me raise that 0% to something higher.You should hope that doesn't happen. But yes, it would force me to think further about my strategy.)
>Voting about things vs. persons is about the same. Condorcet is a good>method if one wants to elect a good compromise winner. In a small>community where people think that they know beforehand how others will>vote, and where the party leaders and strategists possibly can force the>voters to vote as told, strategic problems are more likely to occur than>in large public elections with independent voters.
We have elections because we can't just invite all the voters to aconference. The voters fill out a ballot and hope that the method will bea good steward of their interests. Legislators usually don't use electionmethods. I would say essentially they figure out among themselves whatthe outcome likely must be and then "elect" it, typically by a majorityvote. If voters could do that directly I think that would be the idealsituation, as far as minimizing the need for strategy.
I'm not sure if you thought I was talking about a legislature usingCondorcet. What I was saying is that I don't think the behavior of alegislature would be emulated well by, for example, picking any arbitraryoption from the top cycle. Some of those options may not be plausibleoutcomes, despite what the pairwise matrix says.
>Yes, Plurality's reference to first preferences is not good. If one >wants to say something more generic that is not tied to first>preference votes, one should reformulate the criterion. The criterion>would not be as sexy that way. Also the use of implicit approval should>be made clearer, if the intention is to say something about voters that>assume it, or a method that makes some use of it.
One idea is that Plurality approximately says that if candidate X winsthen there should be some way to place approval cutoffs within therankings such that X is the approval winner. (First preferences comeinto play because it's assumed no one would disapprove those.)
Kevin
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