[EM] IRV vs Plurality

[Abd ul-Rahman Lomax]

At 04:05 PM 1/25/2010, Juho wrote:
>I reply to myself since I want to present one possible simple method
>that combines Condorcet and added weight to first preferences
>(something that IRV offers in its own peculiar way).
>
>Let's add an approval cutoff in the Condorcet ballots.

Highly recommended. I also highly recommend explicit approval cutoff 
on Range ballots, it then becomes possible to sense majority 
approval, which is, in practice, quite important in the general 
election case, allowing any method to be used with a standard 
majority-of-the-votes approval requirement for any democratic decision.

>  The first
>approach could be to accept only winners that have some agreed amount
>of approvals. But I'll skip that approach and propose something
>softer.

I.e., normally, a majority. Or sometimes lower than that, or some 
margin of victory requirement that, ideally, is successful in 
predicting majority approval in a runoff election.

>  A clear approval cutoff sounds too black and white to me
>(unless there is already some agreed level of approval that must be
>met).

I've proposed a midrange approval cutoff as standard in range ballots 
because of the simplicity, and it dovetails with the concept of 
equality of expression as to positive and negative opinion, and allow 
discrimination of a "lesser-of-two-evils" vote from a "both 
acceptable" vote. If our goal is broad public satisfaction as to 
results, making decisions based on the lesser of two evils isn't a 
good idea, unless, of course, it is the lesser of two evils itself, 
with no better choice being possible!

>The proposal is simply to add some more strength to opinions that
>cross the approval cutoff.

Bucklin does that, basically, by only considering approval votes, but 
it sets up a declining approval cutoff, typically in three batches, 
loosely named as Favorite, Preferred, and Approved. I've suggested 
that in a runoff voting situation, majority required, "Approved" has 
a very specific meaning: it means "I would prefer to see this 
candidate elected over holding a runoff election." Voters, then, by 
what candidates they choose to approve given their overall 
understanding of election possibilities, will sincerely vote this. It 
makes no sense not to.

>  Ballot A>B>>C>D would be counted as 1 point
>to pairwise comparisons A>B and C>D but some higher number of points
>(e.g. 1.5) to comparisons A>C, A>D, B>C and B>D. This would introduce
>some approval style strategic opportunities in the method but basic
>ranking would stay as sincere as it was. I don't believe the approval
>related strategic problems would be as bad in this method as in
>Approval itself.

I suggest looking at Bucklin. In Oklahoma Bucklin, which was declared 
unconstitutional before ever being used, fractional votes were 
assigned to lower preferences, making this the first attempted Range 
method in the U.S. It is a shame that the framers of the law place 
mandatory ranking in it, in a misguided attempt to push for 
majorities, for that was the basis for rejection, not the 
multiple-vote aspect of Bucklin or the fractional votes.

>Counting only first preferences would not be a good approach since it
>should be possible to vote e.g. X>Y>>.... when X is my favourite
>candidate of my favourite party and Y is the strongest candidate of my
>favourite party.

Bucklin allows this vote, easily. But parties would generally be 
advised to avoid multiple candidates running in the same election. It 
is a bad idea for many reasons, if they already know -- and they 
should know -- which candidate is the strongest. It isn't just vote 
splitting, it is splitting up campaign funding, much of which is 
devoted to generating name and affinity to name.

Bucklin is ranked approval voting. Not for public elections yet, but 
for theoretical consideration, I've proposed Range/Bucklin, where the 
method simulates a series of repeated elections (not "runoff 
elections" with reduced candidate sets, a basically bad idea, unless 
very good selection of the candidate set is used that would include 
any condorcet winner and any range winner, for starters) with 
declining approval cutoff. The voter controls the level at which the 
approval votes are cast.

This method then seeks to find majority approval, one step at a time. 
It thus provides limited later-no-harm protection for the voter, it 
only brings in lower preference votes at a point where it's clear 
that a majority can't be found without them. And the method might 
terminate at midrange, or perhaps a bit below midrange, and this 
would, of course, affect voter strategy.

But something else becomes possible. The method sets up an incentive 
for the voter to vote preferences accurately, I believe. If it does, 
the method will vote intelligently in the voter's interest. Given 
that, the range votes themselves, in toto, should be quite useful. 
I'd suggest that whenever the range winner is different from the 
Bucklin winner, as defined, and if the difference is significant 
(which should be precisely defined, of course), the range winner 
would be included in any runoff election.

Analysing methods like this could be quite complex, but the first 
part (the Bucklin election) simulates what would happen in a real 
series of repeated elections, missing only the additional advantages 
of closer examination by the electorate, it is still based on a 
snapshot on election day. The range analysis predicts two things: 
overall real satisfaction including all ratings, and election turnout 
in a runoff. Weak preferences don't encourage voters to turn out and 
vote, so real preference strength is tested.

This latter phenomenon has generally been overlooked in considering 
the effects and implications of runoff voting, and it probably 
improves the quality of results according to absolute differential 
utility summation.

>This is just a simple method to demonstrate that if one wants to put
>some extra weight on first preferences also Condorcet methods could be
>modified to cover such needs. There may be different requirements on
>what kind of first preferences or "core support" should be given
>additional weight. Depending on that definition also other kind of
>Condorcet variants could be developed.

By definition, range methods put extra weight on first preferences, 
if the voter chooses to express the first preference exclusively, as 
does Bucklin, at least in the first round.

>This method could be used to reduce the chances of candidates from
>minor parties (with no strong "core support") to win. I'm not saying
>that that is a general target, but if someone wants to set that target
>then this type of approach could be used. The point is that Condorcet
>could also emulate, approximate or even improve some of the properties
>of IRV if needed.

Sure. And allowing equal ranking would improve IRV, and keeping the 
majority requirement for election, under some conditions, will also 
improve IRV, probably greatly. (In real runoff elections with top two 
runoff, which will almost always imitate IRV if a majority of votes 
cast are required, and looking only at nonpartisan elections, the 
runner-up goes on to win the runoff, whereas with IRV, it almost 
never happens. Real runoff elections test voter preferences, and weak 
preferences don't result in votes, as a general principle. Thus, I 
expect, if voter turnout is considered, we can expect real runoffs to 
pick the social utility maximizer of the candidates eligible to 
receive votes in the runoff.)

Note that the form of IRV that Robert's Rules *actually* describes 
(contrary to FairVote propaganda repeated all over the place) 
requires a majority of votes or the election is repeated, without 
eliminations. I believe new nominations are even required, but they 
should certainly be allowed even if existing candidates were 
automatically nominated, or some were automatically eliminated but 
could be restored by some process.

Hey, what if any candidate could get on the runoff ballot if the 
collection of such candidates guaranteed, by deposit, the payment of 
the runoff election costs.... Or signatures of registered voters in 
lieu of the payment or as part of it?

The idea would be to guarantee that a truly supported candidate could 
keep in the race. If the candidate wins .... the public treasury 
covers the payment. Not an idea thoroughly worked out, to be sure.....