[EM] Why I think IRV isn't a serious alternative KD

[James Gilmour]

Kevin Venzke  > Sent: Tuesday, December 16, 2008 1:49 PM
> The reason I believe LNHarm is more valuable than 
> monotonicity is that when a method fails LNHarm, the voter is 
> more likely to realize in what insincere way to vote 
> differently, in order to compensate. When a method fails 
> monotonicity, a voter will rarely know to do anything 
> differently because of it.

LNH is important to ordinary electors, as I have explained in a recent post, at least where the voting system is susceptible to LNH
effects.  If the vote counting method is not LNH-compliant, electors are likely to vote strategically in an attempt to avoid or
mitigate the effects of LNH-failure or to try to gain some real or imagined advantage from its effects.

Monotonicity, or more specifically, the lack of monotonicity, is of no importance whatsoever in public elections because neither
candidates nor voters can exploit it.  It would be "nice" if the vote counting system were monotonic, but we cannot have
monotonicity AND some of the other criteria we consider desirable.  For example, monotonicity and later-no-harm are incompatible in
IRV and STV-PR.  Of the two, LNH is important  -  non-monotonicity is irrelevant.

James Gilmour
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