[Election-Methods] SPPA - support building engine

[Stéphane Rouillon]

Great, the link seems not to work directly. Then use:
http://convention2.allacademic.com/one/mpsa/mpsa07/
select authors as research matter in the upper left and type Rouillon.
It should work.
By the way, Quebec MMP analysis report is published today:
I'll provide the web site as soon I know it.

Thanks Yves,

Steph.

>   ----- Original Message -----
>   From: Stéphane Rouillon
>   To: Steve Eppley
>   Cc: election-methods at electorama.com
>   Sent: Thursday, December 20, 2007 6:36 PM
>   Subject: [Election-Methods] SPPA - support building engine
>
>
>   As asked for: a link to SPPA paper presented at Chicago in April 2007.
>   
>http://convention2.allacademic.com/one/mpsa/mpsa07/index.php?click_key=1&PHPSESSID=a6f3cb6bdfc80d157cec9e6b5ffc0add
>   IRV is the single winner method used as engine to determine the support 
>for each candidate in this case.
>
>   Steve Eppley a écrit :
>Hi,
>
>It was not that I didn't read the rest of Stephane's earlier message.
>It was his lack of clarity: His next example looked like he switched to
>a different voting method, because his description of the tallying was
>very different and he did not indicate he was using the same method
>("Repetitive Condorcet (Ranked Pairs (Winning Votes)) Elimination.").
>
>At this point, I will assume Stephane does not intend to provide a
>definition of that voting method nor a link to it, and I don't have time
>to hunt in older messages to see if it was defined once upon a time.
>
>Regards,
>Steve
>-------------
>Stéphane Rouillon wrote:
>   My advice to Steve is to read all an email before comments.
>Cut-off were applied further building the counter-example in the part
>he snipped...
>Of course without cut-off, the original ordering method comes back.
>
>"meaningless winners which could not get elected with SPPA in the end."
>
>refers to the fact that the multiple-winner method will not
>necessarily elect a candidate that received the most support
>in a district. Again, it is a matter of considering an election as a
>representative exercise and not as a battle.
>
>Stéphane Rouillon
>
>Steve Eppley a écrit :
>     Hi,
>
>Stéphane's latest example (immediately below) is very different from
>his earlier example that I quoted (further below) which he tallied
>using a voting method he called "Repetitive Condorcet (Ranked Pairs
>(Winning Votes)) Elimination."  His earlier example had no "approval
>cutoffs" and his latest example appears to have no connection to
>Ranked Pairs or Condorcet.  Thus he hasn't provided a basis for
>claiming my comment was wrong.
>
>My advice to Stéphane for when he sobers up (just joking) is to
>reread his earlier example and then provide a clear definition of the
>"Repetitive Condorcet (Ranked Pairs (Winning Votes)) Elimination"
>method, or a link to its definition, so we will know what voting
>method he was writing about.  Based on the name he gave it and from
>his earlier example, it appears (to me, at least) to be the method
>that iteratively eliminates the candidate ranked last by MAM until
>one remains.
>
>The thrust of my comment was that since MAM satisfies Peyton Young's
>LIIA criterion, it follows that MAM elects the same candidate as the
>more complex voting method that iteratively eliminates the candidate
>ranked last by MAM until one candidate remains.  Was Stéphane
>claiming this is wrong, when he wrote that my comment was wrong?
>
>Second, I do not understand what he meant where he wrote,
>"meaningless winners which could not get elected with SPPA in the
>end."  I suspect it is not relevant to the comment I made.
>
>--Steve
>---------------------------------
>Stéphane Rouillon wrote:
>
>       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
>votes as support.
>   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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