[EM] ironclad pro-Condorcet argument?

[Dave Ketchum]

 From below I quote:

> But this Robert's procedure nevertheless satisfies the 
> Condorcet criterion, which requires the election of the 
> Condorcet winner if there is one.
> 
Robert's is into repeated balloting, using the full slate of candidates, 

which usually (BUT NOT ALWAYS) elects the CW (if I have to do a demo for 

nonbelievers, it ain't that hard).


Among my reasons for choking on including repeated balloting are that IRV 
uses the same voting as Condorcet, and also USUALLY elects the CW, and I 
choke on IRV for what it does in its exception cases.  AND I believe most 
will agree that IRV should not be lumped in with Condorcet.

Trivia:  I see reference to "Robert" below, as if a reference to one 
person.  Trouble is, the only one person was General Robert, who died in 
1923.  The work has been carried on since then as a family effort.

DWK

On Tue, 24 Aug 2004 10:04:14 -0700 Steve Eppley wrote:

 > Dave K wrote:
 >
 >>On Tue, 24 Aug 2004 01:06:48 -0700 Steve Eppley wrote:
 >>
 >>>Dave K wrote:
 >>>
 >>>>On Mon, 23 Aug 2004 11:29:48 -0700 Steve Eppley wrote:
 >>>>
 >>>-snip-
 >>>
 >>>>>Another positive argument for Condorcet-consistency
 >>>>>uses the single-elimination pairwise voting procedure
 >>>>>recommended by Robert's Rules,
 >>>>>
 >>>-snip-
 >>>
 >>>
 >>>>>Most of the people reading this, I assume, are aware that
 >>>>>under the Robert's Rules procedure, the Condorcet winner
 >>>>>(when there is one) will be chosen, assuming either
 >>>>>that every voter votes sincerely or that every voter is
 >>>>>strategically sophisticated and knows the preferences
 >>>>>of all the voters.
 >>>>>
 >>>>HUH???  The Robert's example is IRV.
 >>>>
 >>AND, they express dislike for Condorcet by their example voting
 >>procedure for preferential voting - the procedure shared by IRV
 >>and Condorcet.
 >>
 >
 > I doubt their omission of Condorcet was an expression of
 > dislike for Condorcet.  Remember, that section was written
 > long before the computer age that made it practical
 > to exhaustively tally all the pairings given voters'
 > preference orders.  And at the time, not a lot of people
 > were aware of Condorcetian procedures.
 >
 >
 >>>No, I wasn't referring to the Robert's Rules IRV example
 >>>of "preferential voting" that they reluctantly recommend
 >>>when the members are scattered, as in a mail-in vote
 >>>(when better methods are impractical, or so they thought
 >>>when that section was written long ago).  I was referring
 >>>to their main method, recommended for use when the
 >>>members are assembled together and hence it's practical
 >>>to use a method that requires multiple rounds of voting.
 >>>This method is sometimes called "agenda voting" and
 >>>sometimes called "sequential pairwise voting."  It
 >>>doesn't ask the voters to express orders of preference.
 >>>And it's like a single-elimination tournament, not
 >>>a round-robin tournament.
 >>>
 >>Please tell me exactly where they, inconsistently,
 >>express approval for Condorcet.
 >>
 >
 > I never claimed they do.  Don't get this discussion of
 > "an ironclad pro-Condorcet argument" mixed up with the
 > recent discussion of the "definition of preferential
 > voting."  What I've been saying is that the voting
 > procedure that Robert's recommends for _normal_ usage
 > within assemblies will elect Condorcet winners.  It's
 > a shame that Robert neglected to mention his procedure
 > will elect Condorcet winners, but that omission isn't
 > critical.
 >
 > It might be worth searching their text for the
 > phrase "best compromise."  Robert criticized IRV
 > because it can easily defeat the best compromise.
 > Maybe he used the phrase elsewhere?  Maybe he even
 > defined it somewhere?
 >
 >
 >>What I see is repeated balloting of the entire question -
 >>not even deletion of weakest candidates, as would earn
 >>the label "runoff".
 >>
 >>
 >>>Here's a simple example:  Someone proposes a bill and
 >>>someone else proposes an amended version of the bill.
 >>>In the first round of voting, those two alternatives
 >>>would be pitted against each other.  The loser of
 >>>that vote would be eliminated.  The winner of that
 >>>vote would go on to the next round of voting,
 >>>a vote between it and the status quo.
 >>>
 >>This example is not Condorcet - in Condorcet all the
 >>versions of the bill would contend in a single election.
 >>
 >
 > Right, we're defining Condorcet as a family of voting
 > procedures that accept preference orders from the voters
 > and elect the Condorcet winner, if there is one, given
 > those votes.
 >
 > But this Robert's procedure nevertheless satisfies the
 > Condorcet criterion, which requires the election of the
 > Condorcet winner if there is one.  It will elect the
 > sincere Condorcet winner given either sincere voting
 > by everyone in each round or strategically-sophisticated
 > voting by everyone in each round.  And it also satisfies
 > the top cycle criterion.
 >
 > The "ironclad" argument is about requiring the election
 > of Condorcet winners when they exist, and within the
 > top cycle in general, since that's what happens in
 > democratic assemblies, where methods better than IRV
 > have long been feasible.  The argument is not about
 > the mechanics, such as whether the votes must be orders
 > of preference.
 >
 > --Steve
-- 
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   Dave Ketchum   108 Halstead Ave, Owego, NY  13827-1708   607-687-5026
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