[Election-Methods] IRV unconstitutional? (replies)

[Stéphane Rouillon]

Yes those flaws exist.
But their FPTP equivalent (vote-splitting) happens very more often than 
the sum of occurence of
the previously cited.

Warren Smith a écrit :
> St.Rouillon:
> IRV defendors should aim at showing that IRV flaws are smaller
> than FPTP flaws, thus FPTP should be declared anti-constitutional if IRV is.
>     
>
> WDS replies: IRV has some flaws which FPTP does not have.  For example,
> non-monotonicity, no-show paradoxes, non-additivity.   I personally think IRV
> *is* better than FPTP (at least if we can ignore issues of simplicity and fraud worries)
> but not in these respects.
>
> For real-world examples of non-monotonic IRV elections featuring no-show paradoxes,
> see 
>  http://rangevoting.org/Ireland1990.html
>  http://rangevoting.org/LizVwiz.html
>
>
>
> Don&Cathy Hoffard:
>   
>> any time a new candidate X entering the race swings the winner from Y to Z, 
>> that benefits somebody (namely Z, here)
>>     
>
> This is not true in most if not all of the [IRV] the General Elections.  90-99% of the General
> elections involve two major candidates and some minor candidates.
> The winner will be one of the major candidates.  In IRV the minor candidates votes are drop and their votes are now cast for one of the major candidates.
>
> You are right in some cases where you have 3 equal candidates.
>
>
> WDS replies:
> I gave constructed examples before of IRV elections where a candidate by entering race
> swings the winner.  E.g. http://rangevoting.org/CoreSupp.html .
> So yes, I am right.   For a real-world example, in the Louisiana 1991 governor race,
> see   http://rangevoting.org/LizVwiz.html
> Duke by entering the race caused Edwards to win, whereas otherwise Roemer would have won.
> So your "if not all" is wrong - there is at least one counterexample. 
> Another is Peru 2006:
> http://www.rangevoting.org/Peru06.html .
> So there are at least 2 counterexamples now.        
>
> Indeed, theso-called "center squeeze" effect in IRV is where it is
> Leftist vs Centrist vs Rightist.
> Centrist is the Condorcet "beats all" winner, but is eliminated by IRV because
> the left & rightists squeeze him into too small a regio of top-place support.
> In EVERY such situation, one extremist, by enteringthe race, swung it to the other
> whereas without him,Centrist would have won.  
>
> THis is quite common: in "1 dimensional politics", this happens 1/3 (33%) of the time
> to IRV.   How we know that: see
> http://rangevoting.org/IrvPathologySurvey.html#csqueeze
>
> So you are quite wrong.  This is not "rare if at all." It is "common."
> The error in your analysis was to only consider the "minor" guy as entering,
> and to neglect the "major" guy as an entrant.  Oops.   When you only
> consider some possibilities you naturally get a lesser count than if you consider them all.
> The underlyign reason for your error was your USA-2007-centric thinking,
> failing to even consider the possibility that a so-called "minor" candidate
> might actually be a Condorcet winner.  IRV leads to 2-party domination
> (a flaw it shares with FPTP) which somewhat "justifies" your error, but that
> is another problem.  :)
>
> --
> Warren D. Smith
> http://RangeVoting.org  <-- add your endorsement (by clicking "endorse" as 1st step)
> and
> math.temple.edu/~wds/homepage/works.html
> ----
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>
>   
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