[EM] IRV in action
bartman at netgate.net
Sat Apr 5 10:58:02 PST 2003
James Gilmour wrote:
> > Dave Ketchum replied
> > Here you need to understand the language IRV uses - they LIKE the word
> > "majority", treading lightly on the fact that they are doing a majority of
> > the ballots that remain to be used to determine a winner, and not a
> > majority of total ballots.
> See my comment above. Whatever other defects it may have, IRV does ensure that
> the winner has the support of half or more of those who are voting at the point
> when the final decision is made.
If my favorite is eliminated, but I despise my 2nd-ranked candidate only
slightly less than my last choice, this doesn't mean I *support* the
2nd-ranked candidate in any meaningful sense. The claim of IRV, or of
any ranked method for that matter, to guarantee a "majority winner" is
based on a fallacy of equivocation-- that the derived majority is
somehow equivalent to an outright majority of voters. In fact the only
way to guarantee a majority is to manufacture one.
A method which randomly dropped candidates until only two remain, and
then selected the remaining candidate with the most votes, would have
just as valid a claim of a "majority winner". You could even
sequentially eliminate candidates with the *most* first choice votes,
until only two remain, and then declare the surviving candidate with the
most votes a "majority winner".
You can also guarantee an artificial majority by preventing all but two
candidates from entering the race in the first place. You can
accomplish this, or at least make it more likely, by adopting
restrictive ballot access rules, or by adopting a two-party-stable
method such as FPTP, two-round runoff, or IRV.
Some would claim that Condorcet methods choose the true majority, since
the Condorcet winner is the majority winner in all pairwise contests.
But since the pairwise majorities are all "artificial" in the above
sense, any aggregation of these majorities will also be an artificial
> > BTW - "majority" is a word that often needs qualification, such as "most
> > of those who voted" or "most of the members".
> "Majority" also needs further qualification when it is used with regard to
> election results. Here in the UK, the word has been distorted from its original
> meaning ("more than half") to mean, in elections, "the winner's lead over the
> second-placed candidate". This distortion of the language goes well with our
> placid acceptance of the distortions of FPTP in single-member districts!!
I'm doubtful that the original meaning of "majority" was "more than
half". As far as I can tell, it simply meant "the larger portion".
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