[EM] IRV vs Condorcet vs Range/Score

[Dave Ketchum]

I suggest a two-step resolution:
      Agree to a truce between Condorcet and Range, while they dispose of 
IRV as being less capable than Condorcet.
      Then go back to the war between Condorcet and Range.

Condorcet uses essentially the same ballot as IRV, with essentially the 
same meaning:
      Any IRV ballot would be acceptable to Condorcet.
      Condorcet also accepts such as A=B.
      IRV often demands that voters vote for more than one candidate; 
Condorcet accepts as few or many as the voter offers.

IRV gives extra credit for ranking a candidate first, while Condorcet cares 
only which is most liked.  The following example shows this:
      IRV starts by discarding B for least first-place votes, and then 
solves A vs C.
      Condorcet sees that B is liked better than A and B better than C, so 
B wins.

Condorcet is better for validation:
      All that is said by a collection of Condorcet voters, such as a 
precinct, can be recorded in an NxN array.  These arrays can be summed for 
whole counties, states, etc.
      When the first name on an IRV ballot loses, such as B in the example, 
the next name on that ballot must be known and substituted.

An example:

42: C>B
39: A>B
10: B>A
4: B
5: B>C

B is the Condorcet winner, and also the first loser discarded by IRV.

Actually, IRV and Condorcet usually agree as to winner:
      If most ballots agree as to top rank, that candidate wins.
      Ditto agreement on most other ballots.
      If there is a near tie among three or more, they often disagree but 
usually get one of the leaders - matters little since the leaders were 
about equally deserving.
      IRV discarding the truly best liked, as in the example, is a strong 
argument for discarding IRV.

My 2-cents as to Condorcet vs Range:

Consider A good, B soso, and C bad:
      In Condorcet I rank A>B>C, expressing my basic opinion.
      In Range I rate A high and C low.  Then I have a headache as to B - 
the higher I rate B, the more danger of B beating A; the lower I rate B, 
the more danger of C beating B.
-- 
  davek at clarityconnect.com    people.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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