At 03:17 AM 12/4/2008, Kristofer Munsterhjelm wrote:
James Gilmour wrote:
Abd ul-Rahman Lomax > Sent: Wednesday, December 03, 2008 10:52 PM
The tragedy is that IRV is replacing Top Two Runoff, an older
reform that actually works better than IRV.
I have seen statements like this quite a few times, and they puzzle
me. I can see the benefit in TTRO in knowing before voting at the
second stage which two candidates will actually be involved in the
run-off. But what concerns me is the potential chaos in getting to
that stage. The French Presidential election of 2002 is a good
example of the very bad results that can come from the first round of
TTRO. And we have seen similar problems in some of the mayoral
elections in England where the so-called Supplementary Vote is used
in which the voters can mark their first and second preferences but
only the second preferences for the first stage Top-Two candidates
are counted. In such circumstances the outcome from TTRO is very bad
and I should have thought that an IRV election would have given a
much more representative result. Condorcet might be better still,
but that's a different debate.
I'm not Abd, but I think the argument goes like this: in TTR, if a
(usually) third candidate gets enough FPP votes to make it to the
second round, that candidate has a real chance of winning, since the
second round will be focused on those two candidates alone, whereas,
on the other hand, if it's IRV, then IRV's chaos may deprive the
candidate of its rightful victory, and even if it wouldn't, people
can only vote for the third candidate that would become the winner
as one of many, not as one of two.
If that's right, then the Supplementary vote should give
significantly worse results than TTR, simply because people can't
discuss and realign between the first and second rounds.
For the benefit of those who aren't familiar with the terminology,
"Supplementary Vote" is top-two batch-elimination IRV. In the United
States, there are or have been a few implementations of SV, and
FairVote claims these as IRV successes.
IRV with sequential bottom elimination is probably better than batch
elimination, because there is, at least, an opportunity for vote
transfers from other eliminated candidate. However, it is far more
difficult to count and what I've seen with U.S. IRV in nonpartisan
elections, the vote transfers tend to not change the positions of the
top three. If we imagine only three candidates, which has been the
case with some IRV elections, this is identical to Supplementary Vote.
For whatever reason, the fact is that in TTR in U.S. nonpartisan
elections (or in party primaries which are effectively nonpartisan in
this sense), we see "comeback" elections where the runner-up in the
primaries wins the runoff, roughly one-third of runoffs. This hasn't
happened yet in these IRV elections in the U.S.
Now, I have not studied the most recent elections. One writer
responded that the Pierce County, Washington, elections showed an
exception. If I'm correct, that was a partisan election. When there
are minor parties present, with relatively predictable vote
transfers, (such as, usually, Green to Democrat), IRV corrects for
the spoiler effect. *However*, don't celebrate!
If the use of a runoff method encourages more parties to be on the
ballot, majority failure becomes common. That is what had happened
with San Francisco, in the nonpartisan elections where they were
using top-two runoff. That will continue with IRV, and it has.
Usually a majority is not found through transfers if it was not found
in the primary, and, in fact, usually the first rank choices
generally express the results after transfers, as far as overall rank order.
This probably makes the world safe for major parties! A third party
is prevented from spoiling elections, which removes some of their
power. Again, for whatever reason, IRV is associated with strong
two-party systems, whereas top-two runoff, around the world, is
associated with vigorous multiparty systems. Both methods display the
problem Mr. Gilmour is concerned about, it's odd that he pins it on
TTR and not on IRV, which is merely *maybe* a *little* better in that respect.
We may speculate that with IRV, Le Pen would have slipped behind
Jospin, thus putting the true top two if second place preferences are
considered into the runoff. To come up with a guess about that would
take more information than I have and effort than I can spare. The
point here is that it can happen, and does happen, that Center
Squeeze pops up, it is not a rare effect. Center Squeeze is certainly
a problem with TTR, but IRV isn't the fix.
IRV fixes the spoiler effect in Plurality, but so does TTR, and so
would other voting reforms, starting with the terminally simple Open
Voting (Approval). Bucklin uses the same three-rank ballot as RCV
(IRV), but allows far more flexibility on the part of voters, who can
use the three ranks to vote for many more than three candidates.
Example. There are twenty candidates, San Francisco has more than
that on the ballot. The voter has a favorite and a second favorite,
but is worried that these are not going to make it to the final
round, and the voter really dislikes a frontrunner. With IRV, the
voter needs to know, to cast an effective vote, who the frontrunners
are, and to make sure that the preferred ones are supported. That can
be quite difficult when there are twenty candidates! Perhaps as a
result, one race in San Francisco, with over twenty candidates, was
won with less than 40% of the vote, there were large numbers of
exhausted ballots.
With a Bucklin ballot, even the Duluth form, where voters could add
multiple approvals only in the third rank, the voter could vote for
sincere favorites in first and second rank, and then for every
candidate but the worst frontrunner -- and also not for anyone worse,
if the voter has such an opinion. With RCV, the voter would have to
guess who else might be in the running in the last round. In France,
they would have guessed wrong, that was the "chaos." Few expected Le
Pen to edge out Jospin. (By less than one percent.)
Allow equal ranking at all ranks and Bucklin becomes easier to vote
than IRV. Very simple and effective strategy:
If you have a reasonable preference, then vote first and second ranks
as unique candidates. If not, then equal rank. You don't have to
choose, you can equally support candidates where you like both and
don't have a strong preference. Then, third rank, you can support
anyone whom you'd rather see win the election than have it go into a
runoff (if a majority continues to be required, which it should). And
if you have a strong preference against one of the frontrunners, you
can apply maximum alternative vote strength by voting for every
candidate better than this one. That's standard Approval strategy,
but, here, it's easy even with three or more candidates.
Bucklin. It deserves much more attention. It was popular. It worked.
It's cheap to count. No eliminations, so no Center Squeeze (unless
everyone bullet votes, but that's very unlikely; majority failure is
more likely in a highly partisan environment, where every voter is
fiercely loyal to their party or candidate and imagines they'd rather
die than see their vote "help" someone else. But we don't need to
drive a stake through the heart of bottom-ranked candidates in order
to satisfy these voters; their lower ranked votes will only help
another candidate beat their favorite, as some would rant and rave
about, if no majority is found and its necessary to start
compromising. Compromising means that you may not get your favorite!
What do we think about people who insist on No Compromise!
Probably much the same as the reviewer of Woodall's original paper
that defined Later No Harm: as to the criterion, disgusted.
In fact, it's not true that an additional vote "helps another hurt
the favorite." It's really an abstention in that candidate pair, a
"stand-aside." It does not act to help the other candidate more than
the favorite; rather it equally helps them.
Note that if we require a true majority, and don't coerce votes (as
in requiring full ranking), no single-ballot method satisfies Later
No Harm. It is incompatible with the requirement that a majority vote
for the winner. "Instant runoff" does not simulate real runoff except
under the artificial constraints of imagining that voters don't
change preferences, the same voters vote, and that voting Bush >
Hitler is a vote for Bush.
The solution to Center Squeeze, which is what happened in France in
2002, isn't IRV, it's using a better first round method, one not
susceptible to Center Squeeze. IRV is very much the wrong choice
there. Approval would work better, no cost. Bucklin would work even
better, probably, using a practical preferential ballot with easy
counting. And no Center Squeeze, almost certainly.
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