[EM] Re: minmax is not a good public election method

Chris Benham chrisbenham at bigpond.com
Tue Jun 21 06:35:44 PDT 2005

You wrote:

>I was quite wrong about MMPO being unable to elect the Condorcet Loser unless
>all candidates have a majority-strength loss. As an example,
>48 A
>2 B=A
>2 B=C
>48 C
>MMPO elects B decisively. So MMPO fails Plurality even worse than I thought.
>I don't know how I forgot this; two-slot MMPO was the first method I advocated
>on this list, and I knew it had this problem then.
A>B 48-2,   C>B 48-2,  A=C 50-50.

I note that all the candidates are in the CDTT (because none of them 
have a majority-strength defeat), and therefore your example also 
applies to CDTT,MMPO.
Also we can add one A ballot, making A the CW (and FPP winner), and get 
the same result with both methods!  (C drops out of the CDTT, but that 
doesn't change the winner.)
Even if we also subtract a C ballot  (restoring  the total to 100 
ballots), then the result for both methods is an AB tie, and if that is 
resolved by Random Ballot then B will have a
4% chance of  winning.

Chris  Benham

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