[EM] Defeat Strength

[Kevin Venzke]

Hi,

I'm afraid that defeat strength is such a tangible concept that it inclines us to view it as
a finished product that we can now simply customize as we please. Or worse: That we are
duty-bound to measure it "accurately." We maximize some desired property, readily identified
within a single pairwise contest, and then apply the minmax algorithm to this ranking, and
expect it to result in a method whose properties have some kind of relationship to the
property we were maximizing, or properties that will at least be as good as the defeat
strength metric sounded.

I couldn't count how many times I had a nice idea, tried to use minmax or River with it,
and discovered some horrible basic flaw. Or just mediocre results.

I see Forest wants to lock a 1%:0% victory first because there is no one around to object
to that particular point. Only the local question is considered, not whether "hard feelings"
might come from some other factor than this. That's the key issue. What can we say about the
overall method that results from applying this logic? We have no real idea, without
checking.

The question then of why anything would "represent defeat strength better than margins" is
strange to me. Defeat strength is just a possible tool to get to the winner. There's no
need for it to represent anything with fidelity to any principle. It might be a marketing
concern, I admit. But when evaluating method properties you only need to know who wins when;
you won't talk about the underlying algorithm and indeed you don't even need to know what
it is.

I don't know what to make of the term "equity" below. Can reducing strategic incentives
cause inequity? How can I tell whether a method is equitable? (Of course then I mean its
*results* being equitable, rather than its method of calculation.)

Usually there's a simple approach to reducing strategy: If a lot of people want something,
such that they could lie on the ballot in order to get it, then just let them have it. Then
that's a complaint of inequity you can avoid, if they were to not get what they want. Maybe
there are other types of inequity, but I'm not sure what, staying within a majoritarian
perspective.

Kevin
votingmethods.net



Le samedi 3 septembre 2022 à 20:31:14 UTC−5, Forest Simmons <forest.simmons21 at gmail.com> a écrit :
> 
> It has more to do with strategy than equity.
> 
> I prefer minimizing opposition to the defeat, because that relieves tension, resentment, and 
> polarization. Perhaps it is possible to win without alienating the opposition, i.e. without 
> all of the bad feelings.
> 
> Notice in the three examples, there was zero opposition against the victory of A over B, so 
> no hard feelings if A beats B.
> 
> On the other hand, the C beats D defeat is highly polarized ... 4999 angry losers.
> 
> But my question which of the three claims is most defensible statistically ... i.e. which one 
> is least likely to be reversed by a random fluctuation in the weather on election day in a parallel 
> universe.
> 
> It seems to me that the margins result (F defeating G) is the most stable in this case. Is 
> that always true?
> 
> 
> On Sat, Sep 3, 2022, 5:33 PM robert bristow-johnson <rbj at audioimagination.com> wrote:
> >  
> >  
> >
> > I never really groked why WV (or LV) would represent defeat strength better than margins.
> >
> > I just don't get it.  WV, that is.
> >
> > - robert
> >
> > Powered by Cricket Wireless
> >
> > ------ Original message------
> > From: Forest Simmons
> > Date: Sat, Sep 3, 2022 8:19 PM
> > To: EM;Richard Lung;robert bristow-johnson;
> > Cc:
> > Subject:Defeat Strength
> >
> > Suppose there are ten thousand voters, and ...
> > A defeats B, 100 to 0, (9900 abstentions)
> > C defeats E, 5001 to 4999, and
> > F defeats G, 1000 to 500 (8500 abstentions)
> >
> > Which pair should have defeat strength priority?
> >
> > Under wv, the (C, E) pair has priority.
> > Under margins (F, G) has priority, and
> > under losing votes (A, B) has priority.
> >
> > But which defeat should be considered most secure statistically? 
> >
> > -Forest
> >
>