[EM] Fluffy the dog: rejection of Condorcet

[Craig Carey]

At 01.09.04 16:40 -0400 Tuesday, Dave Ketchum wrote:
 >On Tue, 4 Sep 2001 08:35:54 -0700 Craig Carey wrote, in part:
...
 >This caught my eye so, thanks to eGroups/Yahoo, I could and did go back
 >to this item in Nov. 00 archives:
 >

I was thinking of my repair to that Fluffy example.


 >I do NOT see this as an indictment of Condorcet.  These voters ALL SAID

Condorcet finds the wrong number of winners sometimes.
Condorcet is able to be seen as already rejected.

...
 >     Aside from the basement thought, I do not like anything that
 >invites strategic voting.  For those who understand the strategy, it

That could be similar to expecting monotonicity to be held.

...
 >As to hundreds of candidates - how can any voter be expected to pick
 >intelligently among such a crowd, regardless of method of counting votes?

Post up the equations and I will have a look at them. Unless there is
some problem with that (nonexistence?).



 > davek at clarityconnect.com    http://www.clarityconnect.com/webpages3/davek
 >   Dave Ketchum     108 Halstead Ave, Owego, NY  13827-1708    607-687-5026
----



This original "Fluffy" example has such problems with its numbers that new
numbers could be used and the original discarded. Here is an improved
version:

       AB  48     : 1 winner        (no. 1)
       B    3
       CB  49

     Condorcet: B wins   :   A:B = 48:52, B:C = 51:49, C:A = 49:48
     FPTP:      C wins

Candidate B wins, and: (1) the outcome is too different to First Past the
Post to some, and (2) allowing that would lead into problems.

Condorcet can be rejected for picking the wrong number of winners even
without this example.

If Mr Layton writes, perhaps an 'improved' Fluffy the Dog example could
be named.


At 2000.11.13 12:05 +1100 Monday, LAYTON Craig wrote:
 >There is basically one cogent criticism of all Condorcet systems, of which
 >you're all aware; that it puts too much importance on middle preferences,
 >especially when not all candidates or parties are known to voters.  Example:
 >
 >In a two candidate race:
 >A 51
 >C 49
 >
 >C wins
  A wins
 >
 >A and C are diametrically opposed, there has been a long and dirty smear
 >campaign, so that C voters hate A and A voters hate C.  My dog, fluffy (B),
 >joins the race at the last minute;
 >
 >ABC 49
 >CBA 49
 >BAC 01
 >BCA 01
             A:B = 49:51,  B:C = 51:49,  C:A = 50:50
 >
 >Fluffy is the Condorcet winner!.
...