[EM] Throwing my hat into the ring, possibly to get trampled

[Kevin Venzke]

Hi Nicholas,



----- Mail original -----
> De : Nicholas Buckner <nlborlcl at gmail.com>
> À : Kevin Venzke <stepjak at yahoo.fr>
> Cc : election-methods <election-methods at electorama.com>
> Envoyé le : Samedi 9 juin 2012 20h23
> Objet : Re: [EM] Throwing my hat into the ring, possibly to get trampled
> 
>T hank you for the article, as it was informative. It is very true that
> Elimination methods tend to eliminate candidates who could go onto
> become winners.

That's not what I'm saying; I'm saying elimination of candidates helps
and hurts the non-eliminated candidates in unpredictable ways.

> QLTD doesn't have a single loser to eliminate (it doesn't mention
> losers much either). In fact I worn against first-past-the-post
> methods (vanilla QLTD) (that's why I go with the "converse" 
> way--the
> elimination way), as they are susceptible to Burying mentioned here
> http://en.wikipedia.org/wiki/Tactical_voting

When you add elimination to a method, it often makes it better, but it
also tends to break some criteria.

> what I think the original article
> (http://www.mcdougall.org.uk/VM/ISSUE6/P4.HTM) tries to show is QLTD
> has a problem with a subset criterion to monotocity he called
> mono-add-top (which is very close to the Participation criterion).
>
> My method doesn't have that problem.  Let me use his example (though I
> have some mild problems with the Droop Quota now, I'll still use it
> for these calculations).

I am sure it does have that problem. Say that the candidates are X Y Z
and X is eliminated and then Z wins. It seems quite possible that you
could add Z>X ballots that cause Y to be eliminated instead of X, in 
which case Z will still be elected only if he beats Y head-to-head as 
well as X.

That's the unpredictability I'm talking about: The Z>X voter would want
Z to continue to win, but the method may use the voter's X preference
to eliminate Y instead of X, causing Z to lose.

Kevin