[EM] 3-slot SMD,ER-FPP(w)

[Chris Benham]

--- En date de : Dim 19.10.08, Chris Benham <cbenhamau at yahoo.com.au> a écrit :
>I have an idea for a new 3-slot voting method:
>
>*Voters fill out 3-slot ratings ballots, default rating is
>bottom-most (indicating least preferred and not approved).
>
>Interpreting top and middle rating as approval, disqualify
>all candidates with an approval score lower than their approval-opposition
>(AO) score.
>(X's  AO score is the approval score of the most approved candidate on
>ballots that don't approve X).
>
>Elect the undisqualified candidate with the highest
>top-ratings score.*
 Kevin Venzke wrote (Mon.Oct.20):


Interesting method, but I'm concerned that rating a candidate in the 
middle can disqualify other candidates, but can't help this candidate 
win, except by preventing him from being disqualified himself. It seems
like a burial risk.

With two major factions supporting A and B, and a third candidate C,
if A faction buries B under C, I believe A will often win. Does B faction
have a defensive strategy that isn't the same as the offensive strategy?
I don't think they do.

Actually, this method isn't that far from MDD,FPP.

CB: Except that method fails Irrelevant Ballots and I think meets LNHarm.

>This clearly meets Favourite Betrayal, Participation,
>mono-raise, mono-append,
>3-slot Majority for Solid Coalitions, "Strong Minimal
>Denfense" (and so Minimal
>Defense and  Woodall's Plurality criterion),
>Independence of  Irrelevant Ballots.

I don't think it satisfies Participation, because your favorite candidate
could be winning, and when your vote is added, you add sufficient
approval to your compromise choice that they are no longer disqualified,
and are able to win instead of your favorite.

CB: Oops!.. you are right. It fails Participation and even Mono-add-Top.

8: C
3: F
2: X>F
2: Y>F
2: Z>F

F wins after all other candidates are disqualified, but if  2 F>C ballots are
added C wins in exactly the way you describe.

It looks like the "Strong Minimal Defense" mechanism is incompatible with
Participation, so I was also wrong in suggesting that my recent "Range-Approval
hybrid" method suggestion meets Participation.

I still like this 3-slot SMD,FPP(w) method however and am confident the other
criterion compliances I claimed for it hold up.


Chris Benham

Send instant messages to your online friends http://au.messenger.yahoo.com 
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.electorama.com/pipermail/election-methods-electorama.com/attachments/20081020/3a7ee64e/attachment-0003.htm>