[EM] Dave: Condorcet

MIKE OSSIPOFF nkklrp at hotmail.com
Wed Mar 28 07:42:49 PDT 2012


You wrote:

Which leaves me promoting Condorcet.  It allows ranking but, unlike  
ABucklin or IRV, all that a voter ranks gets counted.  Further, any  
voter able to match their desires to Plurality or Approval for a  
particular election, can vote by those rules and have them counted  
with the same power by Condorcet rules.


Several problems with Condorcet:

1. Any method at all more elaborate than Approval, and especially a method
as different and elaborate as Condorcet is going to be much more suspect
than Approval is, to the public. Opponents will be able to say, "We don't
know enough about this voting system. It needs much study." Approval is
unique among voting system reform proposals, in that it's so simple, and such
a small modification of Plurality, that it's easy to show that it's an improvement
on Plurality, and only an improvement. That's much more difficult for more
complicated methods such as Condorcet.

2. For a handcount, Condorcet has much more count labor than does Approval.
If there are N candidates, then there are N(N-1)/2 pairs of candidates. For each
voter, a vote is counted among each pair of candidates. Now, in Approval, let's
estimate that, on the average, a voter approves half of the candidates. N/2 
approvals to be counted per voter. That means that Condorcet has (N-1) times more
votes to be counted, as compared to Approval. Sure, the Condorcet handcount needn't 
take longer, if you hire more counters. But, for one thing, the count is equally
more expensive, whether you hire more counters to work the same hours, or the 
same number of counters to work longer. Besides, the more count-work there is,
the more opportunity and risk for count-fraud there is.

3. Condorcet fails FBC. Though it's unlikely, there are situations where you
can only prevent a worse result by favorite-burial. No matter how rare those
situations are, some, probably many, people will favorite-bury therefore, because
, for many people, helping their "lesser-evil" is everything. With Approval, ABucklin,
MCA, MTA, and their conditional versions, and also with ITC, it's possible to 
_guarantee_ that there can never be any reason to vote anyone over your favorite.

Even if you only value reason #1, above, that alone is reason enough to only propose
what is proposable, enactable _now_.  Approval.

One other thing: I used to claim that burial strategy is well-deterred in Condorcet.
But now I admit that I was only considering 3-candidate elections. With more candidates
burial isn't well-deterred. If I can find a candidate who will be sufficiently well-beaten,
then I and my faction can safely make hir soundly pair-beat the sincere CW, without risk
of electing that candidate whom we're ranking over the sincere CW.

ICT has some good protection against burial, because burial can only work for a
candidate who is ranked #1 by more people than anyone else in the cycle.

ICT would be a better proposal than Condorcet, since it also meets FBC and CD (it's
defection-resistant, unlike Condorcet). But ICT share's Condorcet's problems #1 snd
#2, above.

Mike Ossipoff
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.electorama.com/pipermail/election-methods-electorama.com/attachments/20120328/02101291/attachment-0002.htm>

More information about the Election-Methods mailing list