At 09:30 PM 1/8/2013, William Waugh wrote:
On Tuesday, January 8, 2013 2:04:06 PM UTC-5, Abd ul-Rahman Lomax wrote:
At 09:34 PM 1/7/2013, William Waugh wrote:
>If I were a strategist for a party that has not had a plurality but
>may be coming close to one, I would see no reason to treat any kind
>of Bucklin election differently from an Approval election, unless I
>am missing something.
It is an Approval election, just staged. Instant Runoff Approval
would be pretty accurate.
>For Approval, I'd have to teach my voters to make randomized choices.
Ah, that's not necessary if the method is Bucklin. This is going too
far. "It's Approval, therefore randomize for an intermediate choice."
In the US presidential election, I expect my opponents to bullet
vote, and I don't expect them to find a majority if my faction is
close to plurality. It will be a three-way race among factions that
are each near 1/3 of the electorate in size. So the Bucklin grades
will collapse together, resulting in an Approval election. So, we
have to use Monte Carlo methods to make the effect that of a Score election.
Real voters don't vote like that! There is an idea here of
"opponents." There is a "U.S. Presidential election," which is a very
unusual situation, an indirect election through a bizarre
misapplication of a old -- great -- idea, that could actually be
Asset voting if electors were assigned through Asset voting on the
state level, which *states could do,* constitutionally. (States have
total freedom and power over how the electors are chosen. The party
system was *not* anticipated, apparently, by the constitutional
convention, and it became established because it favored the majority
party in each state, and for that majority party to go to a fair
distribution of electors would be politically suicidal if others did
not go the same way.)
In a three-party system, as described, a voting system is severely
challenged. But that system is highly artificial and unrealistic.
Yes, you could realistically have a three-party system were first
preference is balanced like that.
But parties don't own voters. And individual voters will vote
differently, depending on their preference strength. Some will bullet
vote (as assumed, and, in fact, if all voters do that, as expected,
*there will be no votes in second and third rank.* But some voters
will add additional preferences, *because their preference for the
Favorite will be weak.* This can be predicted from any normal
distribution in issue space.
The assumption here is pure Bucklin, plurality win.
Yes, voters can add randomized choices for an effective intermediate
vote, but where would this vote be placed? 2nd rank? 3rd rank? If
second rank, it's silly; instead, one would just use third rank. If
3rd rank, sure.
However, there is a much better choice: fix the voting system to
handle this kind of situation better. There is some question of how
far we should stand on our heads to handle a situation that is highly
unlikely to arise. What's seen in many-party TTR elections is huge
vote-splitting, with two parties leading, but still with less than
30% of the primary vote. There is no doubt but that Bucklin would
pull up the numbers. Voters could express a clear favorite, providing
valuable information, while also participating in a *virtual runoff.*
France could use Bucklin for their Presidential primary. There is
practically no doubt that it would improve election performance,
given historical data.
So how to improve on Bucklin. I have generally assumed Bucklin, now,
as a primary method in a maximum two-round runoff system. We know
that simulations show that runoff range improves performance over
single-ballot range, given realistic voters.
(If voters voted "accurate sincere utilities" this improvement would
not happen. If they vote "strategically," which is how people make
choices, in the real world, the improvement is definite. If they
simply normalize, normalization error can occur, and normalization is
probably essential.)
If a Range ballot is used, and if it includes Approval information
(which is simplest by considering 50% range or above as "approval"),
we have a fairly simple system for Runoff Range. To win the primary,
one must have the highest Range vote *and* majority approval. If no
candidate has majority approval, there is a runoff. This will handily
address Mr. Waugh's situation, in fact. If they want, they can
express their preferences in below-approval range, bullet voting for
the Favorite *as to approval.* Or if their preference is weak, and
they would rather avoid a runoff if possible, they can add an
above-approval additional preference.
But more becomes possible. The Condorcet Criterion is the most
intuitively appealing of voting systems criteria. Because a Range
ballot allows pairwise comparison, the votes can be tested for a
Condorcet winner who would *not* appear on the runoff. If one exists,
then the runoff candidates would shift. It's possible for a runoff,
with an advanced ballot, to have more than two candidates, but it
might just be simpler to make the contest in the runoff be between
the Range winner and the Condorcet winner. (i.e., a little more
broadly, any candidate who beats the Range winner pairwise. That
*could* be three, and I'd want to study the situation in detail to
determine an optimal choice under that circumstance.)
Bucklin starts as descending cumulative approval. Traditionally, it
terminates once a majority is found. Because of the possibility of
multiple majorities, how to handle them must be scrutinized. Multiple
majorities may represent *real approval* of more than one, or could
represent poor strategic voting choices. Runoffs *test preference
strength,* and this must be understood to understand the value of
runoffs. They also produce a difficult-to-quantify value, increased
scrutiny of a reduced candidate set.
Dark horses *can win* with runoff voting, because the bar is lower.
In TTR, they only have to make it to second place to get into the
runoff, and suddently they are not dark horses any more. They are
frontrunners, and their supporters will turn out in droves in the
runoff. It becomes a real race! And this is probably why there is a
"comeback election" in about a third of real nonpartisan runoffs, a
phenomenon that hardly ever happens in IRV, as a simulation of
runoff. The plurality leader almost always wins IRV, because the
voters supporting eliminated candidates appear to be a fair sample of
the whole electorate *as to preferences among the remaining candidates.*
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