[EM] Consensus?: IRV vs. Primary w/Runoff

[Markus Schulze]

Dear Mike,

you wrote (4 Feb 2002):
> Markus wrote (4 Feb 2002):
> > In so far as IRV meets majority for solid coalitions and independence
> > from clones, IRV can hardly be called "erratic" compared to primary
> > with runoff.
>
> IRV is erratic because it requires strict ordering, collects a ranking,
> and then makes irreversable decisions based only on a fraction of
> the ballots' information, looking only at 1st choice votes.

That's also true for the instant version of primary with runoff.

******

You wrote (4 Feb 2002):
> Sounds good, but a mutual majority is also a situation where IRV
> will demonstrate its failures of FBC & WDSC, showing its lesser-of-2-evils 
> problem and its gross and avoidable violation of majority rule.
>
> Say you believe, rightly or wrongly, that there's a majority who
> prefer both Worst & Middle to Favorite. Why should you vote Favorite
> in 1st place? No reason to. He can't win. But you can gain by voting
> Middle in 1st place, in case he needs your vote to avoid immediate
> elimination and the subsequent transfer of his votes to Worst.
>
> The Clone Criterion, too, is about a special case. Sure, with IRV,
> adding clones won't hurt your faction, but other ordinary & typical
> situations will make IRV violate FBC & WDSC.

That's no argument since primary with runoff violates your FBC and your
WDSC too.

My argument is that in so far as IRV meets majority for solid coalitions
and independence from clones, IRV can hardly be called "erratic" compared
to primary with runoff. You didn't address my argument. Check the
paragraph of mine that I copied above, and which you'd quoted before
your "reply".

Markus Schulze