Diego Santos wrote:
Many members of this list prefer a Condorcet method to any other voting
method, especially if it meets Smith. But how vulnerable are ranked
methods to strategic voting?
Consider these two assumptions:
1. Sincere Condorcet cycles would are too rare if used in real elections.
2. Strategies are somewhat common in contentions elections.
Compromising is almost unnecessary in River, Schulze or Ranked Pairs,
but these methods are vulnerable to burying. And still if a sincere
Condorcet winner exists, these methods have a possibility to elect a
Condorcet loser, because only rankings don't provide enough information
to find the sincere winner in all situations.
I don't have a proof, but I think that if a sincere Condorcet winner
exists, Smith//approval is the only method resistant to both
compromising and burying strategies. This property is valid in all
3-candidate scenarios.
Because Smith is more complex to explain, my current favorite election
method is Condorcet//Approval. We don't need complex algorithms to find
a winner.
You could also have the approval version of Smith,IRV. Call it
Condorcet,Approval. I think it's Smith (so it would be Smith,Approval),
but I'm not sure. The method is this: Drop candidates, starting with the
Approval loser and moving upwards, until there's a CW. Then that one is
the winner.
Is Condorcet,Approval (Smith,Approval?) nonmonotonic? If not, and it is
Smith, then you have a simple Smith-compliant Condorcet/approval method.
These methods would obviously need approval cutoff ballots (unless you
go with the MDDA assumption, that the approval cutoff is where the voter
truncates, but I don't think that would be a good idea here).
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