[EM] Re: IRV letter

[Bart Ingles]

Chris Benham wrote:
> 
> To seriously make the case that IRV is not better than Plurality,
> instead of talking about the made-up example a person
> should
> (a) make the case that compliance with mostly sundry mathematical
> neatness criteria (like Participation and  Monotoncity)
> weigh as much as compliance with  (mutual) Majority  and  Clone
> Independence.

Any particular reason that the burden of proof should be on those
favoring criteria other than Mutual Majority and Clone Independence?

Regardless, I give at least as much weight to FBC and freedom from
Duvergerian equilibria.  My reasoning is that if there are always two
strong parties, there is really no need to look further at election
method properties.  Voters will either vote so as to favor one of the
two relevant alternatives, or abstain in order to cast a protest vote.

Clone independence seems worthwhile, in that substantial failure would
result in either a Duvergerian system or a rich-party problem.  But I
don't see any practical value in Mutual Majority, which if met by IRV
must be similar to Condorcet Loser.


> (b) and/or  point to some computer simulations which show something

Merrill's simulations show plenty.


> (c) and/or maybe even point to some real-life examles. IRV  has been in
> use in public political elections for most of a century.

...with apparently the same two-party outcomes as Plurality over the
long haul.  Even if you view this as anecdotal and not proof of a
two-party bias, there is still a lack of evidence to the contrary. 
Which is where the burden of proof should be if attempting to push
through an expensive "reform".

Bart Ingles