[EM] Condorcet corresponding to some variant of IRV?

[Dave Ketchum]

On Mon, 26 May 2003 00:37:20 +0200 Bjarke Dahl Ebert wrote:

 > Here's an idea:
 >
 > If you modify IRV to not cancel first votes when progressing to secondary
 > votes, would that method find the Condorcet Winner?


BIG question is:  WHY WOULD YOU WANT TO?
       Where can you find any happiness by, supposedly, doing IRV, but
sometimes picking a different winner than IRV would?
       How can you dependably pick the CW without doing the Condorcet method?
       Why not look closer at Condorcet and start thinking of a way to make
clear to voters that the CW is the best way to honor their desires?

Let us do similarities first:
       Ballot is identical.
       For MOST elections the two methods produce identical results.

Differences:
       Condorcet backers can point with derision at IRV, in some cases,
declaring the obviously best liked candidate to be a loser (IRV backers
can sometimes hide this problem by not explaining what they are doing).
       When looking only at each voter's first choice does not provide a
winner:
            IRV discards part (or even all when truncation is involved) of
what some voters have said, and analyses whatever non discarded data remains.
            Condorcet looks at whole ballots, finding comparative liking of
each pair of candidates.  It does not have the IRV problem of sometimes
discarding information about a candidate before finding out whether that
information is important.
            IRV's method of discarding can result in radically different
results from trivial differences in ballots (such as adding a few absentee
ballots received after election day, that affect which candidate has the
least votes and therefore gets discarded first).
            Condorcet records all that each voter has said, and has no
order of discarding to complicate processing.
       For electing mayors, governors, senators, etc., results from many
election districts must be combined.
            For IRV these are complex lists, but must be combined before
there is anything explainable.
            For Condorcet result is a simple NxN matrix of counts for N
candidates - easy to sum for multiple districts and easy to make public in
understandable form (for individual election districts or any combination
such as a county) - for each pair of candidates, how many liked A>B and
how many liked B>A.

As to what follows - to be a workable public election, polls have to be
open for some period during which each voter votes ALL they wish
to indicate about each contest.  AFTER the polls close, what has been
voted gets analyzed.
       If I understand what I read below, it depends on a dynamic process
in which all the voters understand all that has been done, and then each
proceed with their next step.

 >
 > Further explanation of the counting algorithm:
 > Everyone votes for their first candidate on the ballot.
 > Then, in each turn, each voter enters a vote for their next candidate on
 > their list, unless the "current election winner" is more preferred by them.
 >
 > Example:
 > 48% A>B>C
 > 25% B
 > 27% C>B>A
 >
 > First round:
 > A: 47%
 > B: 25%
 > C: 27%
 >
 > Now, the 27% will place a vote for B also:
 > A: 48%
 > B: 52%
 > C: 27%
 >
 > So B is the winner.
 >
 > This can be seen as a "simulated series of Approval Voting elections". In
 > each turn, voters lower their "threshold for approval", until they are
 > satisfied with the current winner.
 >
 > This method will always find a unique winner (unless there is vote count
 > equality, of course).
 > Questions:
 >   A: Will this winner always be in the Smith set?
 >   B: If there is a Condorcet Winner, will it be the same as the one 
found by
 > this method?
 > (A implies B).
 > In case of B, it could serve as an alternative justification of Condorcet
 > Voting: "Just like IRV, but don't forget candidates just because they were
 > temporarily discarded (until we knew better)".
 >
 >
 > Kind regards,
 > Bjarke

-- 
   davek at clarityconnect.com    http://www.clarityconnect.com/webpages3/davek
    Dave Ketchum    108 Halstead Ave, Owego, NY  13827-1708    607-687-5026
               Do to no one what you would not want done to you.
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