My points are that:
Condorcet presents the SAME ballot rules to the voter as IRV -
simply relaxed a trifle - a voter could vote by IRV rules, successfully.
While Condorcet analyzes the ballot more like what would pass for
tournament rules, it will usually agree with IRV as to winner:
IRV cares only about front runners, discarding what it sees as
the weakest of these and declaring the strongest remaining as winner.
Condorcet compares every pair of candidates as in a tournament
(how many A>B (A ranked and B ranked lower or not ranked) vs B>A (B ranked
and A ranked lower or not ranked). The candidate winning every one of its
pairs is winner. Front runners that IRV looks for are in a good position
to win such a Condorcet tournament.
Carrying IRV's front runner emphasis to extremes, both would declare A the
winner in the following:
2 A
1 B>A
1 C>A
3 D>A
4 E>A
10 F>A
20 G>A Point here is that this constructed pattern let A beat G
21>20 by IRV rules, while many somewhat similar patterns would have let A
win in Condorcet - which does not care if A is ever a front runner - only
about its complete liking.
Implementing programming differs among these election methods - but they
are not especially complex, beyond ability to read ranked voting, and
voters need not worry about details.
IRV needs an array with a member for each candidate, counting front
runners. Once the least popular is identified, the ballots need
recounting of who is front runners among those not yet discarded.
Condorcet needs an NxN matrix to count all the A>B and B>A values, but
only needs to read each ballot one time for this. Ok to read ballots into
multiple matrices, such as one per precinct, for such can be summed into a
result matrix.
SHOULD be of interest to voters that the matrix describes liking levels
among all the pairs of candidates - useful for analysis and planning for
future.
Condorcet cycles are near ties of three or more candidates such that each
almost wins - A except for B>A, B except for C>B, and C except for A>C.
Voters need to know this much, and programmers need to be able to defend
their resolution to those voters asking for such.
-------- Original Message --------
Subject: Re: [Election-Methods] A Better Version of IRV?
To: EM <election-methods@lists.electorama.com>
On Sat, 12 Jul 2008 21:09:15 +0300 Juho wrote:
On Jul 12, 2008, at 17:56 , Kristofer Munsterhjelm wrote:
Dave Ketchum wrote:
Again, why NOT Condorcet?
Its' ballot is ranking, essentially the same as IRV, except the
directions better be more intelligent:
Rank as many as you choose - ranking all is acceptable IF you
choose.
Rank as few as you choose - bullet voting is acceptable if that
completes a voter's desired expression.
Equal ranking permitted.
Condorcet usually awards the same winner as IRV. Major differences:
Condorcet looks at ALL that the voters rank, while IRV ignores
parts.
Condorcet recognizes near ties, and tries to respond accordingly.
Could be a debate about the near ties - would it be better to
resolve such with a runoff? Runoffs take time and are expensive.
Are they enough better than what Condorcet can do with the original
vote counts?
On technical merit alone, why not Condorcet indeed? But the thread
was about momentum. In the situation where IRV can't be stopped, what
is the best way to nudge IRV towards something more desirable while
still keeping it IRV-ish enough that it'll retain the momentum of
"pure IRV"?
I argue above that Condorcet, using the same ballot and usually finding
the same winner, is about as close to IRV as could be reasonably asked.
One very simple approach would be to promote ranked methods as one
group. Just join the bandwagon, include all methods and leave the
details of the method to be decided later (pick the best then). The
delta from plurality to ranked methods and achieved improvements are clear.
One modification that's been mentioned before is bottom two runoff -
eliminate the one of the two last placed that fewer prefer to the
other. That would ensure a Condorcet winner always wins, but to core
IRV supporters, that's a weakness, because the Condorcet winner could
be a weak centrist. The ameliorated procedure would also fail LNHarm.
If the people on which the momentum is based would support any sort
of elimination procedure, then I think Borda-elimination would be
better; so what one really has to ask is, if IRV is unstoppable, then
how far from pure IRV can you go and still have it be IRV? IRV with
candidate withdrawal? IRV with candidate completion? BTR-IRV?
Schwartz,IRV? Any sort of elimination system? Any sort of ranked
ballot system?
One argument against Condorcet, which one may call half-technical, is
complexity. It's technical because it regards the method itself and
not whether Condorcet Winners are good winners (or similar), and
nontechnical because what's complex to a computer may not be complex
to a person and vice versa.
What the voter needs to know is not complex. Debating how to resolve
cycles is complex, but the implemented election method needs little more
than that it should be rare and is a bit better than a lottery among
almost equals.
That the debating and implementing is a challenge, but the voters
need not be concerned - except those who are gluttons for punishment.
As far as complexity with regards to Condorcet goes, the good
Condorcet methods are complex. Schulze may be easy to program (once
you know the beatpath algorithm), but explaining beatpaths to the
average voter is going to be hard. Copeland is easy but not very good
and ties a lot.
Some Condorcet methods are simple, like minmax. It is good too. I note
that you later referred to cloneproof methods as good methods. Minmax
is not fully cloneproof but I don't think that is a problem. (Same with
not being fully Condorcet loser compliant.)
If your favourite Condorcet method is complex then it may better start
with promoting Condorcet methods in general. I think it is in any case
a mistake to dive into the details of the methods when promoting an
electoral reform. Citizens and politicians are simply not interested in
such dives (would be counterproductive). Better to use some more
general arguments that are linked to the reform needs at more general
level.
One thing I've observed is that IRV focuses on how the process is
done, while Condorcet methods focus on properties ("the winner is the
candidate which wins all one-on-one contests"). I'd say explaining
properties would be more easily understood than explaining the
process, but apparently this isn't a great limitation for IRV, given
its momentum so far.
IRV is typically described as it it was a "public fight" between
candidates where the candidates are eliminated one at a time. This is a
very appealing style because of the very real life like and exiting
image it offers. The description also sounds quite fair (at least at
first sight).
So I listened to those who call Condorcet a tournament with the winner
winning the election.
There are also differences in how different Condorcet methods are
described. To me methods that are justified using (possibly long) beat
paths are philosophically different from methods that are based on
evaluating the more local properties of individual candidates (e.g.
minmax).
(Also the philosophy of finding a complete ordering of the candidates
is different from the philosophy of just identifying the best candidate
without establishing a complete order. The interesting point is that
individual preferences of the voters are usually expected to linear
while it is known that group opinions may well be cyclic (just a
natural property, not a fault that should be somehow corrected).)
Doing complete ordering has to be more complex than finding a single winner.
Cycling is natural, but only matters when candidates are near enough to a
tie to make it possible.
Perhaps Ranked Pairs would have a chance? It's one of the better
Condorcet methods (cloneproof, etc), and if people accept the
pairwise comparison idea, it should follow quite easily. Say
something like that you can't please everyone all the time, so please
most, which is to say that one locks preferences in the order of
greatest victories first. Then anyone complaining because his group's
(cyclic) preference was not locked could be rebutted by a larger
group saying that if it had been, more people (namely, that larger
group) would have been overridden. Here you have both method
(locking) and properties (group complaint "immunity"), as well.
It'd be interesting to investigate which simple or intuitive methods
are the best. I don't know what would constitute simple to voters,
perhaps "Of those candidates that [some statement], choose the one
that [some statement]", or "[Somehow reduce the set of candidates]
until [criterion is met], then that one is the winner" for various
sentence parts inside the brackets. Those are all method-based
explanations; maybe property-based ones would be better. If the voter
trusts that the method does what the property says, and the property
is desirable, then that could be the case.
I'll continue my "minmax campaign" a bit more. The best part of minmax
(margins) (and the reason why I'm interested in it) is that it has a
very natural (and easy to understand) description and justification. It
elects the candidate that needs the least number of additional votes
(if any) to win each of the other candidates (in pairwise comparisons).
I'd say that is a reasonably good description of a candidate that
deserves to win (if one is looking for a good compromise candidate).
Methods for resolving cycles are important, but are best left as a detail
to be debated AFTER resolving the other major details.
Juho
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Dave Ketchum 108 Halstead Ave, Owego, NY 13827-1708 607-687-5026
Do to no one what you would not want done to you.
If you want peace, work for justice.
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