[EM] Defeat Strength

[James Gilmour]

Kristofer
If the last statement in your message below is correct, about how IRV been sold, all I can say is that those responsible have been
engaged in serious misselling.

My description, well amplified by you, of how IRV works and is intended to work, is exactly as you set out below.  That is because
IRV, and STV more generally, is a contingency voting system.  It always has been, and it always will be.

Yes, that means IRV and STV-PR fail Condorcet and are not monotonic.  But STV does comply with LNHarm, a criterion that is important
to real voters in real elections.

James Gilmour


Kristofer Munsterhjelm   > Sent: 09 September 2022 21:16
> As I understand it, James considers an IRV ballot to be a kind of program instruction, so that e.g. voting A>B>C is a way of
telling the voting method "I want my ballot to count towards A until he's eliminated; then I want my ballot to count towards B
until/unless he's eliminated, etc".
> 
>  From such a perspective there is no failure because the voters gave the method certain instructions, and the method obeyed these
instructions, and the winner was who was elected since that's what the procedure says.
> 
> If I understand that right, then there's no promise of a vote counting towards B if A can't win, because B could be
> eliminated before A and so the ballot skips directly from A to C. Which leads to Condorcet failure, nonmonotonicity, and so on.
> 
> Since IRV passes both LNHarm and LNHelp, the procedural interpretation does happen to coincide with the (method- independent) idea
that unranked candidates should be considered to rank below every explicitly ranked candidate, because that's the effect not ranking
candidates has on the method. But if the method were different, the procedural interpretation would also come to a different
conclusion.
> 
> (However, I don't think the procedural interpretation is particularly common; at least it isn't how IRV has been sold.)
> 
> -km