[EM] Condorcet loser elimination PR
James Green-Armytage
jarmyta at antioch-college.edu
Mon Jul 28 12:24:39 PDT 2003
Dear Chris,
When I said that Hare or Droop didn't matter for this, I was referring to
the purpose of illustrating the basic flaw in your revised method, which
is defined by a concept rather than any particular example. I did not mean
that it wouldn't affect the outcome of the example I gave. I intended the
example as illustration, from which you could infer from it the underlying
principle or idea that I was trying to communicate, which is independent
of Droop or Hare.
Anyway, I have modified my previous example so that it gives the same
result with Droop or Hare.
Previous example:
300 votes
3 seats
Hare quota = 100
86: A, B, C, D, E
15: B, A, C, D, E
100: C
15: D, E, C, B, A
84: E, D, C, B, A
Modified example:
300 votes
3 seats
Droop quota = 75
74: A, B, C, D, E
39: B, A, C, D, E
75: C
39: D, E, C, B, A
73: E, D, C, B, A
Once again, I would say that the appropriate result would be ACE, but I
believe that your revised method gives an outcome of ABC. Hopefully this
makes things more clear.
I chose the Hare quota for the first example just for the sake of
tidiness. If it bothers people, I suppose that I might as well start using
the Droop quota for my examples.
At this point I will agree with you and James that the Droop quota is
preferable to the Hare quota. I found James's example to be very strong.
my best,
James
>James,
>I seriously doubt your claim that using a Hare instead of a Droop quota
>"doesn't
>matter for these purposes". I remember long ago getting it on good
>authority that
>compared to the Droop quota, the Hare quota is correctly superceded
>rubbish. This
>view has been recently confirmed by James Gilmour:
>
>"When Hare and Droop are applied to transferable preferential voting (eg
>STV-PR),
> the effect of the Hare quota to over-represent smaller groups can deny a
>larger
> party its fair share of the seats to the extent that it gets fewer seats
>than a
>smaller party with fewer votes."
>
>In the case of your example, the Droop quota is 300/4 = 75. Since ACE
>each have
>more than a Droop quota of first preference votes, then I and my proposed
>method
>agree that ACE is the "appropiate outcome".
>So I am afraid I don't understand your point.
>
>Looking forward to your reply,
>
>Chris Benham
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