[EM] Instant Runoff Voting 3-candidate elections - pathologies considerably more common than you may have thought

[Jonathan Lundell]

On Aug 27, 2010, at 12:48 PM, robert bristow-johnson wrote:
> 
> with Score and Approval, it's easy to mark your favorite candidate (Score=99 or Approval=1).  and we know that Satan gets Score=0 or Approval=0.  then what do you do with other candidates that you might think are better than Satan?  that question has never been answered by Clay.  and any answer must be of a strategic nature.

That is, to my mind, a fundamental problem with cardinal-rating systems--approval, borda, range, etc. Except for some trivial cases (notably two-candidate elections), the voting act is necessarily a strategic exercise. With an ordinal method (IRV, Condorcet (though one could I suppose specify a non-ordinal cycle breaker), Bucklin) it's at least possible (and usually a good idea) to cast a sincere ballot.

Why the latter is a good thing is a separate discussion...