[Election-Methods] Unnecessary voting method?

Stéphane Rouillon stephane.rouillon at sympatico.ca
Mon Dec 17 18:50:38 PST 2007

```First Steve's comment is wrong as shown below: A > B > C.
> 33: A > B | C
> 31: B > C | A
> 33: C | A > B
> 3:   B | A > C
>
> C is eliminated with 33 votes as support.
> B is eliminated with 34 votes as support.
> A is last eliminated but receives no rallying voters and finishes with 33
>
> B wins.
Second, as written before, scores or supports matter, not meaningless
winners which could not get elected with SPPA in the end...

S.Rouillon

Steve Eppley a écrit :
> Hi,
>
> Assuming I'm correctly understanding a voting method Stéphane Rouillon
> used in a recent message (excerpted below), which he called "Repetitive
> Condorcet (Ranked Pairs(Winning Votes)) elimination," it is
> unnecessarily complicated because it chooses the same winner as Ranked
> Pairs(Winning Votes), which of course is simpler.
>
> Ranked Pairs(Winning Votes), also known as MAM, satisfies H Peyton
> Young's criterion Local Independence of Irrelevant Alternatives (LIIA).
> One implication of LIIA is that elimination of the last-ranked
> candidate(s) does not change the ranking of the remaining candidates.
>
> By the way, a different criterion has been masquerading as LIIA in
> Wikipedia.  Peyton Young defined the real LIIA in his 1994 book Equity
> In Theory And Practice (if not earlier).
>
> --Steve
> --------------------------------------
> Stéphane Rouillon wrote:
> -snip-
>
>> Let's try a counter-example:
>>
>> 3 candidates A, B, C and 100 voters.
>> Ballots:
>> 35: A > B > C
>> 33: B > C > A
>> 32: C > A > B
>>
>> Repetitive Condorcet (Ranked Pairs(winning votes)  ) elimination would
>> produce
>>
>> at round 1:
>> 68: B > C
>> 67: A > B
>> Thus ranking A > B > C
>> C is eliminated.
>>
>> at round 2:
>> 67: A > B is the ranking
>> B is eliminated
>>
>> at round 3:
>> A wins.
>>
> -snip-
> ----
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>
>
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