[Pnp-wg] Full IRV example, was Re: Interim report sections (fwd)
Steve Greenfield
bicyclesax@earthlink.net
Sat, 23 Apr 2005 08:32:57 -0400
I'm don't think that Steve Kramer's illustration is a fatal flaw in IRV, in
fact, depending on philosophy of how you interpret "score," it might not be
a flaw at all and may be another of its strengths, just one that is not
necessarily instinctively seen at first glance.
In example one, Smith has a plurality as a first choice, but hardly anyone
wants him/her as the second choice, and s/he is rated third by even more
people than those who rate him/her first. Smith's campaign has inspired very
firm convictions both for and against. S/he never played to the middle.
Loved or hated. Same thing with Johnson, except in reverse. More people are
firmly against Johnson than for him/her, and not too many people are voting
for "I don't love Johnson but I can live with him/her." Allen wins easily
with second-choice votes added to his/her competitive first-round first
choices, and the majority of Smith's supporters aren't terribly broken
hearted, because most of them voted Allen as their second-choice fully aware
that Allen was who they would get if their first-choice, Smith, did not
prevail in round 1, regardless of whether Smith was failing to achieve a
simple majority in round one or if s/he was the dropped low-tally candidate.
In example two, Smith wins for the simple reason that passionate support or
opposition to him/her has modified to the point where s/he is more
acceptable as the middle ground fallback position for more voters. As s/he
was always the first choice of the plurality, and is now more acceptable to
the middle than s/he was in example 1, his/her victory is not a big
disappointment for too many people..
Since one of the beneficial consequences of IRV is to lead candidates
towards promoting their issues rather than attacking each other, and
therefore the entire dynamic of an IRV race is different than a
winner-take-all plurality race, it's not necessarily appropriate to rate the
candidates' "scores" according to traditional WTA understandings. One of the
great strengths of IRV is to give the center its chance to win without
eliminating the ability of the extremes to run hard and gain first-choice
votes without their voters fearing spoiling by not voting for the centrist,
and hopefully giving the extremes a chance to win out-right if a majority
ends up supporting them in the first (or first + second, if they have paid
attention to trying to appeal to the center as well as the extreme) rounds.
It also gives the extreme voter a chance to salvage a victory for the
centrist through the addition of their second-choice votes. This is what
happened in Example 2, and therefore Smith's victory in the context of the
IRV dynamic can just as easily be considered another manifestation of the
strength of IRV.
Of course Steve K. is right that something weird happens, but I think it's a
philosophical weirdness rather than a mathematical one. The traditional
American WTA mindset regarding all competitions does not lend itself easily
to new electoral dynamics, and it could take a century of cooperative
competition before the understandings that underlie it become ingrained in
the American conscience the way WTA victory is ingrained today. I'm
optimistic it could someday happen, because in sports round-robin and
double-elimination contests enjoy popularity alongside the more violent
single-elimination contests. But something weird happens somewhere in any
system. As no perfect system exists, the best we can do is try for the least
imperfect, which to some degree depends upon philosophical agreement over
the most and least desirable imperfections.
Personally, I like IRV. It has a simplicity element arguing in its favor, as
well as the innovative cooperative-competition philosophy that for many will
have to be an acquired taste.
Steve Greenfield.
----- Original Message -----
From: "James M Leas" <jolly39@juno.com>
To: <Pnp-wg@lists.gp-us.org>
Cc: <tbour@verizon.net>; <terryb@fairvote.org>
Sent: Saturday, April 23, 2005 7:09 AM
Subject: Re: [Pnp-wg] Full IRV example, was Re: Interim report sections
(fwd)
> Steve Kramer,
> Did you see the article in Scientific American last year on majority
> voting methods? IRV was mentioned but not given much space because,
> according to the article, it did not necessarily provide the outcome
> desired by a majority of the voters, as your example below illustrates.
> The article actually focused on another system that it said was better at
> providing majority rule. I think that system looked at more than just the
> first place choices, as IRV does.
>
> I wonder whether anyone in the Greens has expertise in this important
> area? Burlington, Vermont voted for a charter amendment to implement IRV
> in the future mayoral elections. If the state legislature and the
> governor approve it could happen next year. But if there is a better
> system we should know about it and consider an amendment for future
> elections.
>
> I would ask, do you only have this problem with IRV if all three have
> lots of votes? If all three candidates have a similar number of votes
> maybe dropping the one with the fewest first place is inappropriate and
> the rankings should all be considered to determine who got the majority.
> Jimmy
>
> On Fri, 15 Apr 2005 01:23:18 -0400 (EDT) Steve Kramer
> <scooter@guisarme.net> writes:
> > Folks,
> >
> > Here is the full example that I sent to Elizabeth earlier. It shows
> > how
> > IRV works, and it also shows that IRV fails the "monotonicity
> > criterion"
> > which I mentioned under "Mathematical Truths". (Plurality/FPTP
> > voting, by
> > the way, *also* fails it.)
> >
> > *Please note* the point I make at the end of this exercise.
> >
> > --
> > Steve Kramer || scooter (at) guisarme dot net
> > ||
> > _____________________
> > ===================================================
> > | __/^\__ ,-^,|
> > |/~ \_ { / | "Power concedes nothing without a
> > demand.
> > \/\ |! | It never has, and it never
> > will."
> > / / ) |___
> > (_ \ \ / Frederick Douglass
> > ~v^ ?_,-'
> >
> > ---------- Forwarded message ----------
> > Date: Sun, 10 Apr 2005 04:51:12 -0400 (EDT)
> > From: Steve Kramer <scooter@guisarme.net>
> > To: Elizabeth Arnone <elizarnone@comcast.net>
> > Subject: Re: Interim report sections
> >
> > On Fri, 8 Apr 2005, Elizabeth Arnone wrote:
> >
> > > However, I don't understand #3 - which says, "no winning
> > candidate should
> > > ever lose as a result of being ranked *higher* by any voter. How
> > would this
> > > happen? Same for #4.
> > >
> > Here's the example. Let's say you hold an IRV election with three
> > candidates,
> > and the following votes are counted:
> >
> > First Second Third
> > 38 voters voted... Smith Allen Johnson
> > 25 voters voted... Johnson Allen Smith
> > 15 voters voted... Allen Smith Johnson
> > 15 voters voted... Allen Johnson Smith
> > 7 voters voted... Smith Johnson Allen
> >
> > Here's how we count this in IRV:
> >
> > Smith has 45 first-place votes, Allen has 30, and Johnson has 25. So
> > Johnson
> > is eliminated. *All* voters who listed Johnson first listed Allen
> > second, so
> > every one transfers over to Allen. Smith now has 45 votes, and
> > Allen has 55
> > votes (30, plus the 25 that were transferred over).
> >
> > Allen wins.
> >
> > Now let's consider if the votes had been slightly different.
> >
> > First Second Third
> > 38 voters voted... Smith Allen Johnson
> > 25 voters voted... Johnson Allen Smith
> > 15 voters voted... Allen Smith Johnson
> > 15 voters voted... Allen Johnson Smith
> > 7 voters voted... Johnson Smith Allen
> >
> > Look very carefully. The **only** thing that changed is that the
> > seven voters
> > at the bottom of the table decided to list Johnson first, *ahead* of
> > Smith. In
> > other words, these seven voters bumped Smith down a bit by not
> > listing him
> > first. This should not help Smith in any way.
> >
> > But here's how it ends up happening in IRV: Smith has 38
> > first-place votes,
> > Allen has 30, and Johnson now has 32. So it's Allen who is
> > eliminated, and his
> > votes are redistributed. As it turns out, 15 of Allen's 30 go to
> > Smith, and 15
> > go to Johnson as second-place choices. Smith now has 53 votes (38,
> > plus the 15
> > he got being second to Allen), and Johnson has 47 votes (32, plus
> > the 15 he got
> > being second to Allen).
> >
> > Smith wins.
> >
> > So...when seven voters list Smith ahead of Johnson, Allen wins. But
> > when those
> > same seven voters switch, and list Johnson ahead of Smith - and
> > nobody else
> > changes a single thing! - then suddenly *Smith* wins.
> >
> > This doesn't *precisely* prove what I wrote above...but it does show
> > that under
> > IRV, a candidate can get a lower "score" and end up winning an
> > election he
> > otherwise would have lost with the *higher* score.
> >
> > And again, whatever method you choose, you'll end up with something
> > weird like
> > this. That's the point of that section.
> >
> > --
> > Steve Kramer || scooter (at) guisarme dot net
> > ||
> > _____________________
> > ===================================================
> > | __/^\__ ,-^,|
> > |/~ \_ { / | "Never was anything achieved without
> > danger."
> > \/\ |! |
> > / / ) |___ Niccolo Machiavelli
> > (_ \ \ /
> > ~v^ ?_,-'
> > _______________________________________________
> > Pnp-wg mailing list
> > Pnp-wg@lists.gp-us.org
> > http://lists.gp-us.org/mailman/listinfo/pnp-wg
> >
> >
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