[EM] Why I think IRV isn't a serious alternative 2
Abd ul-Rahman Lomax
abd at lomaxdesign.com
Thu Dec 25 11:48:28 PST 2008
At 03:36 AM 12/25/2008, Kristofer Munsterhjelm wrote:
>Do you think my runoff idea could work, or is it too complex?
For years, attempts were made to find a majority using advanced
voting methods: in the U.S., Bucklin was claimed to do that, as it is
currently being claimed for IRV. (Bucklin, in fact, may do it a
little better than IRV, if voters vote similarly; my sense is that,
in the U.S. at least, voters will respond to a three-rank Bucklin
ballot much the same as an IRV one, so I consider it reasonable to
look at analyzing IRV results by using the Bucklin method to count
the ballots. If the assumption holds -- and prior experience with
Bucklin seems to confirm it, Bucklin detects the majority support
that is hidden under votes for the last-round candidates.
The methods generally failed; holding an actual runoff came to be
seen as a more advanced reform, worth the cost. All this seems to
have been forgotten in the current debate. Bucklin, IRV, at least one
Condorcet method (Nansen's, apparently) have been used.
The error was in imagining that a single ballot could accomplish what
takes two or more ballots. Even two ballots is a compromise, though,
under the right conditions -- better primary methods -- not much of one.
When considering replacing Bucklin or IRV with top two runoff, what
should have been done would have been keeping the majority
requirement. This is actually what voters in San Jose (1998) and San
Francisco (2002) were promised, but, in fact, the San Francisco
proposition actually struck the majority requirement from the code.
Promise them majority but given them a plurality.
If the methods hadn't been sold in the first place as being runoff
replacements, we might have them still! The big argument against
Bucklin, we've been told by FairVote (I don't necessarily trust it)
was that it did not usually find a majority. There is little data for
comparison, but I do know that quite a few Bucklin elections that
didn't find a first preference majority *did* find a second or third
round one, but in the long Alabama party primary series, apparently
there was eventually little usage of the additional ranks. But even
the 11% usage that existed could have been enough to allow the
primary to find a compromise winner. What they should have done, in
fact, was to require a runoff, just like they actually did, but
continue to use a Bucklin ballot to try to find a majority. This
would avoid, in my estimation, up to half of the runoffs. Since
Bucklin is cheap to count and quite easy to vote, this would have
been better than tossing preferential voting entirely.
Sure. Setting conditions for runoffs with a Condorcet method seems
like a good idea to me. One basic possibility would be simple: A
majority of voters should *approve* the winner. This is done by any
of various devices; there could be a dummy candidate who is called
"Approved." To indicate approval, this candidate would be ranked
appropriately, all higher ranked candidates would be consider to get
a vote for the purposes of determining a majority.
In Range, it could be pretty simple and could create a bit more
accuracy in voting: consider a rating of midrange or higher to be
approval. This doesn't directly affect the winner, except that it can
trigger a runoff. Not ranking or rating sufficient candidates as
approved can cause a need for a runoff. If voters prefer than to
taking steps to find a decent compromise in the first ballot, *this
should be their sovereign right.*
A Range ballot can be used for Condorcet analysis. Given the Range
ballot, though, and that Range would tie very rarely, it seems
reasonable to use highest Range rating in the Smith set, if there is
a cycle, to resolve the cycle. Thus we'd have these conditions for a runoff:
(1) Majority failure, the Range winner is a Condorcet winner.
(probably the most common). Top two runoff, the top two range sums.
(2) Majority failure, the Range winner is not a Condorcet winner.
TTR, Range and Condorcet winner (cycles resolved using range sum).
(3) Majority, both Condorcet and Range, but Range winner differs from
Condorcet winner. same result as (2).
(4) Majority for Range winner, not for Condorcet. or the reverse. I'm
not sure what to do about this, it might be the same, or the majority
winner might be chosen. A little study would, I think, come up with
the best solution.
Range is theoretically optimal, as optimal as is possible given an
assumption that most voters will vote a full strength vote in some
pair. However, normalization or poor strategy can result in
distortion of the Range votes compared to actual voter utilities. One
of the symptoms of this might be Condorcet failure for the Range
winner. If it is true that the Range winner truly is best, then we
have a situation where the first preference of a majority might not
be the Range winner, or, supposedly, the Range winner vs the
Condorcet winner might award the election to the Condorcet winner.
But, in fact, it is normal for small electorates to set aside the
first preference of a majority in favor of some greater good. I see
no reason not to extend that as a possibility to large electorates.
My own opinion is that, *if the Range votes are accurate*, the Range
winner will normally beat the Condorcet winner, because of
differential turnout and weak preferences that reverse during the
runoff campaign. On the other hand, having this runoff possibility
answers the common objection to Range: majority criterion failure.
With a runoff system like this, MC failure doesn't occur, because the
majority in the final and effective election has voted for the winner.
(That's not 100% absolute, if write-in votes are allowed in the
runoff, as I believe they should. But if the runoff is, say, Bucklin,
maybe two-rank, I think that spoiled majorities will be relatively
rare, and that the elections that end up with a plurality would
almost always be resolved the same way if an additional runoff were
held. Thus, short of Asset Voting, this could be almost perfect.
Want perfect? Asset Voting, which bypasses the whole election method
mess! Single-vote ballot works fine! And that's what many or even
most voters know how to do best.
I originally proposed that the first reform in the U.S. to focus on
was Open Voting, Count All the Votes, i.e., Approval, because of its
terminal simplicity and the probability that no harm would be done,
the scenarios of multiple majorities with a mediocre candidate
elected are highly improbable. We might go many, many years before we
see a multiple majority, and then it would be because two quite good
candidates were running. We should be so lucky!
However, Bucklin, when a majority hasn't been found in a round,
gradually becomes full Approval. The claim that Approval hasn't been
used in the U.S. was just plain false, it's part of the Bucklin
method. The use of the ranks, seeking a majority, makes Bucklin more
likely to add additional approval, which is what ranking candidates
in Bucklin must be considered. If they are used, that's what they
are. My sense is that this is sufficiently adequate for voters as
protection of their favorite; the only difference between this and
IRV is that with IRV, your candidate has to be taken out and shot,
er, eliminated, before your additional preference can be revealed,
whereas with Bucklin, there are no eliminations, so, yes, your vote
for another has effectively, and only if there is majority failure,
just in that specific pairwise election, abstained, it has *not*
actually "hurt" the candidate. And, in return, your candidate might
actually win instead of being eliminated. Which one is help and which
one is hurt?
In any case, it seems that Bucklin voters did add substantial numbers
of additional preference votes, at least in the municipal elections.
So I've shifted to proposing Bucklin, though Approval remains a
simple, do-no-harm, cost-free reform. Introduce it to a TTR system,
some runoffs may be avoided. Introduce Bucklin, more.
There is a variant of Bucklin that was a Range method: Oklahoma. That
alone should have received some attention! Unfortunately, I think no
election was ever held, because the reformers overreached, and
example of how a bright idea might not be. *Require all voters to use
all three ranks!* I.e., don't count their vote if they don't. The
very system used in Australia to guarantee a "majority." And, of
course, under that situation, with full ranking, it is an absolute
majority, if we disregard the spoiled ballots.
In any case, the Oklahoma court tossed it out because of that
disregard of perfectly plain votes for a favorite. Rightly so, in
that respect. What wasn't so right was that they did not merely
declare that particular provision void, as the minority opinion
claimed should have been done. They just voided the whole thing.
But Range Voting, a ranked form, was written into law in the U.S., I
think it was about 1915. Dove v. Oglesby was the case, it's findable
on the net. Lower ranked votes were assigned fractional values; I
think it was 1/2 and 1/3. Relatively speaking, this would encourage
additional ranking, I'd expect.
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