[EM] IRV vs Plurality

[Kathy Dopp]

> Date: Wed, 13 Jan 2010 22:24:53 -0500
> From: Abd ul-Rahman Lomax <abd at lomaxdesign.com>
> To: robert bristow-johnson <rbj at audioimagination.com>,  EM Methods
>        <election-methods at lists.electorama.com>
>
> At 02:14 AM 1/13/2010, robert bristow-johnson wrote:
>
>
>>>IRV/STV is fundamentally unfair because a large group of persons whose
>>>first choice loses, never has their 2nd choice counted,
>>
>>only if they don't mark their 2nd choice.

IRV promoters should do due diligence to understand how IRV works.
There are several scenarios where voters' marked 2nd choices are never
counted, even when their first choice loses, and this is what makes
IRV/STV such a fundamentally unfair system that tends to elect extreme
right or left candidates while eliminating the majority favored
candidates.

Cases when voters' 2nd choices are never counted include:

1. 2nd and later choices eliminated prior to 1st choice, and the most
important case

2. the very large group of voters whose 1st choice makes it to the
final counting round and then loses

The above will *always* happen in all IRV/STV elections. In
particular, #1 above occurs anytime that there are a number of
candidates that is greater by one (1) than the number of ballot
positions.

This fundamental inequity is what causes nonmonotonicity, elimination
of majority-favorite candidates, and the fact that commonly IRV/STV
does not find majority winners because so many voters' ballots are
exhausted prior to the final counting round, thus involuntarily
excluding a large number of voters from participating in making the
final decision as to who is elected.

I truly cannot imagine a worse voting method than IRV/STV which fails
more of Arrow's fairness criteria than plurality voting does.

Kathy


>
> No. Damn it, I wish people would make more effort to understand the
> scope of the problem! Robert, I expect you to say Ooops!
>
> I vote for A and for B as a second choice. In the first round of IRV
> counting, B is eliminated. My second choice is never counted, because
> my first choice, A, was still standing when B was eliminated.
>
> That's the effect of the Later-No-Harm compliance of IRV, and a
> simple example of the destruction LNH wreaks. It doesn't matter if B
> is the Condorcet winner by a landslide, if B is the second choice of
> every voter, with vastly higher satisfaction overall if elected, that
> first preference vote, to the FairVote activists and anyone who
> drinks their Kool-Aid, is sacrosanct.
>
> Even if a "first preference vote" is with very low or even absent
> preference strength. Try to equal rank in first preference, or any
> preference, and you know what the IRV counting rules will do, don't
> you. Tell me why the system throws that information out? It has an
> obvious meaning! It means that the voter is claiming to be equally
> satisfied by the election of either candidate!
>
> IRV with equal ranking allowed would be a much better method;
> basically it would be Approval voting in first round, or later
> rounds. But Bucklin is more straightforward and far easier to
> understand. The elimination algorithm of IRV is just plain weird and
> chaotic, take a look at those Yee diagrams. It looks simple. It is
> far from simple.
>
>>   otherwise, that's
>>certainly not true.
>
> Well, Robert has a golden opportunity now. He can recognize that he
> can be certain about a thing and be dead wrong. That is
> extraordinarily valuable! Take the opportunity, Robert, I promise you
> that the pain, if there is even any, will be transient, and, in the
> long run, you'll even be happy you made the mistake.
>
>>   ("unfair" is subjective, but the latter half is
>>untrue for voters who mark a 2nd choice with 3 credible candidates.
>>or do you mean that if they vote for the 2 biggest losers, their 3rd
>>or 4th choice that *does* count in the final round isn't their 2nd
>>choice so it's unfair?)  IRV is screwed up, but you still have made
>>no case that the weird pathologies of IRV are worse than the widely
>>known pathologies of plurality in a multi-party or multi-candidate
>>context.
>
> The original comment was quite correct (but, yes, "unfair" is
> subjective unless qualified, but, indeed, it could be qualified with
> reasonable fairness criteria). Suppose there are three credible
> candidates, we'll call them A, B, and C. No, the example given isn't
> what's being talked about. The statement is literally true. Except by
> op-scan ballot images that show those second choice votes, they are
> literally never counted. With hand counting, they would never be
> counted. I think you'd better review how IRV works! When a candidate
> is eliminated, votes for that candidate are not counted from that
> point on, and if they haven't been counted before that, they are
> never counted. So with IRV, it is quite clearly true that it's
> possible that every single voter votes for a candidate, casts a vote
> for a candidate, and the candidate is not elected. You may think
> that's fair, but I don't. When that happens, not every vote was
> counted and my slogan is
>
> Count All the Votes.
>
> (And, of course, use them!)
>
> To make this crystal clear, let's suppose that A, B, and C are
> relatively equal in popularity. And we can assume no complications
> with additional candidates, there are only three. So I vote A>B. But
> because B, it turns out, gets the lowest vote count, maybe it's, say,
> 32%, 34%, 34%, or it's even 33%, 33%, 34% but B's is a vote less or
> loses the coin toss, B is eliminated. My second rank vote for B is
> never counted. And if the votes were this:
>
> 33% A>B
> 33% B
> 33% C>B
>
> Consider what this means. It means that every single voter considered
> B acceptable, because every single voter voted for B. The B voters
> are in the middle, say, and really don't care which of A or C are
> elected, they are both equally unpalatable to them. They are
> centrists, and they recognize the harm to the country if an extremist
> is elected, which A and C are from their point of view.
>
> But because of a small vote gap or a coin toss, B is eliminated, and
> only one-third of the actual votes for B are ever counted and
> considered. Now, tell me, is this fair. What do you think, really?
> Stand aside from everything you have thought or said before, does
> that sound fair?
>
> Sure, this is an extreme example. But in real life, the margin of
> acceptability of the B candidate can be quite high. Montrose in
> Burlington wasn't just the Condorcet winner by some small margin, it
> was substantial. Montrose would have won under Bucklin, I have no
> doubt, Bucklin handled elections like this, historically, with ease.
> Montrose would likely have been the Range winner, and was almost
> certainly the social utility maximizer. (Which is slightly different
> from being the Range winner because voters will vote strategically to
> some degree or other).
>
>>>unlike some other voters. It's a highly inequitable method.
>>
>>not as inequitable as plurality.   why is reducing the information
>>obtained from the electorate more equitable?
>
> It's equitable because it is equal. What's inequitable is collecting
> a lot of information from voters, then only using some of it in a way
> that effectively disenfranchises some.
>
> And, please, remember this. The purpose of elections is to pick a
> winner. IRV in nonpartisan elections so frequently picks the
> candidate who is the first preference winner (by plurality plus, of
> course, when it happens by a majority, which is the norm with small
> candidate counts) that we might as well say "always." We can assume
> that voters, with IRV, under present conditions (not necessarily
> after they get wise to how the method works), are voting sincerely.
> So with Plurality, they will either vote sincerely and get the same
> result at much lower cost and certainly an easier voting decision, or
> they will modify their vote according to their understanding of
> what's practical.
>
> Let me explain how I'd do this. With plurality, if I have an
> understanding of the situation and there are more than two viable
> candidates, as far as I know, I will probably vote for my favorite
> from among all those whom I consider might have a chance. With no
> such knowledge, I will probably just vote for my favorite without
> restriction. Why not?
>
> People don't go through complicated game theory analysis to vote. In
> nonpartisan elections, they don't have the party endorsement to go
> by, so what do you think they do? They vote for their favorite!!!!
> And only if their favorite is truly minor, and they know that their
> favorite can't win, and we must assume that they will usually be
> right about that, will they vote strategically, for a favored
> candidate from among the realistic possibilities. The result,
> basically, Plurality will produce the same results. Period. With
> nonpartisan elections.
>
> Now, when was the last time you heard the words "nonpartisan
> elections" from FairVote? Yet that is exactly where they have been
> selling IRV, the place where it is utterly and completely useless and
> quite possibly harmful. Burlington was partisan, so Burlington showed
> how, with partisan elections, the spoiler effect can be avoided,
> perhaps, but then IRV makes the wrong choice as to the winner.
>
> And all those Wright>Montrose votes: they weren't counted for
> Montrose. They were moot, because Montrose was eliminated first, before Wright.
>


-- 

Kathy Dopp

Town of Colonie, NY 12304
phone 518-952-4030
cell 518-505-0220

http://utahcountvotes.org
http://electionmathematics.org
http://kathydopp.com/serendipity/

Realities Mar Instant Runoff Voting
http://electionmathematics.org/ucvAnalysis/US/RCV-IRV/InstantRunoffVotingFlaws.pdf

Voters Have Reason to Worry
http://utahcountvotes.org/UT/UtahCountVotes-ThadHall-Response.pdf

Checking election outcome accuracy --- Post-election audit sampling
http://electionmathematics.org/em-audits/US/PEAuditSamplingMethods.pdf