[Election-Methods] Fwd: [LWVTopics] IRV Voting

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From: Kathy Dopp <kathy.dopp at gmail.com>
> 

Comments below

> ---------- Forwarded message ----------
> From:? <LWVTopics at yahoogroups.com>
> Date: Sat, May 10, 2008 at 7:22 AM
> 
> Pathological scenarios
> can be constructed for all voting systems, including whatever ones Kathy
> may prefer to IRV.

Diagrams from Ka-Ping Yee show that IRV is very weird when compared to 
other methods.

They are a bit complex, but are very informative once you get them.? They
allow voting methods to be compared visually.

http://zesty.ca/voting/sim/

Also, his results were replicated elsewhere:

http://bolson.org/voting/sim_one_seat/www/
http://rangevoting.org/IEVS/Pictures.html
http://ivnryan.com/ping_yee/results.html

Also, IRV suffers from centre squeeze.? This means that a compromise
candidate who would be mid-way between the 2 main contenders cannot
win.

> Yes.? I prefer IRV to all other systems for electing a single winner to
> an executive office because it elects a majority winner in a single
> election without the need for a separate expensive runoff election. 

Maybe.? It depends on how you define majority.

For example

45: A>B>C
40: B>C>A
15: C

C gets eliminated in the first round and A wins with 45 of the remaining
votes (85), so he has 53% of the remaining vote but only 45% of the votes
cast.? This is a majority of the remaining votes but not a majority of 
the cast votes.

> I'm not sure how Kathy defines "support", but it must be different from
> how I would define it.? IRV uses the same basic logic as a traditional
> runoff election to find a majority winner.? Any argument along the
> lines Kathy presents is equally true of IRV AND traditional runoff
> elections.? Imagine a traditional runoff election (or IRV election)
> with three candidates, A, B, and C.? If A gets 48%, B gets 46% and C
> gets 6%, the runoff would be between A or B.? Now let's say all the C
> voters prefer B over A, so B ends up with 52% to A's 48%.

The situation is that:

C beats A
C beats B
A beats B

Shouldn't C win ?

More importantly, if A or B were to decide not to run, then C wins 
with IRV.

I think the above example could be described as something like

48%: Love A, like C and hate B
46%: Love B, like C and hate A
6%: Love C

A is loved by 48%
B is loved by 46%
C is at least liked by everyone

It isn't obvious that electing C is a bad choice.

> I don't think most people would support a system
> that would declare the winner of a 3-way race the candidate who was the
> first choice of only 6% of the voters.

First choices aren't everything.? C gets 1st or 2nd choice from everyone.

Also, neither A or B are 1st choice of a majority.

> But all
> of them agree that our current election method, plurality elections
> (complete with the spoiler problem), is the worst method.

Right, plurality is useless.? However, IRV might be only slightly better.

It does eliminate the spoiler, but only when the 3rd party is small.

In Australia where it is used, it maintains the 2 party system, so if
helping 3rd parties have a chance is your goal, then IRV isn't going
to help much.

> The vast majority of informed opinion (not just that of the
> IRV-dislikers) is that IRV is the best option for single-seat
> elections. ?

> >Also some other reasons not to promote IRV (besides the fact that it
> >often ends up putting candidates into office that are not supported by
> >- or even are opposed by - a majority of voters) include:
> 
> It is theoretically possible to have an election in which NO candidate
> has majority support, like a rock, paper, scissors endless loop, but IRV
> is FAR more likely to elect a true majority choice than our current
> plurality election method with its rampant spoiler problem.

The condorcet loop doesn't apply to IRV.

The reason that the winner can sometimes not have majority support is 
that some ballots will 'exhaust'.? If all the candidates on the ballot
have already been eliminated (Say the voter only votes for 1 candidate
and he is eliminated), then the total number of ballots remaining drops.
This means that you can get more than half of the votes in the last
round with less than half of the votes cast in the first round.

> IRV has been counted easily and quickly in recent U.S. elections in
> places like Burlington, Vermont, and Cary, North Carolina.? Auditing
> can be more complicated, simply because there is more information from
> each voter to double check, but can also be more thorough. ?

Another issue is that it requires a central office to handle the counts.
With plurality (and many other systems), each polling station can 
announce its results and then they are added together by the central
office.

With IRV, they must all be sent to a central location for counting, 
or each?round must be completed locally and then new instructions sent
based on the result of each round.

> San
> Francisco and Burlington, for example, posted a record of every
> ballot's set of rankings on the Internet, allowing anyone to tally
> those elections themselves.

That's pretty cool, and should be encouraged as long as paper ballots
were used. ?

Was it electronic voting?? If so then the cure is worse that the disease.

IRV may end up encouraging electronic voting due to its counting complexity 
with all the security issues that leads to.

> As to IRV not achieving its "claims":? There are two claims often made
> for IRV that may be somewhat over-stated.? Although political
> scientists and courts have recognized IRV as a majority voting method,
> it is possible that some voters will not rank either of the two
> finalists in the runoff count. ?

Right, it comes down to how you define majority.

Also, with IRV we are only sure that the final winner is prefered to one
other candidate (the one he beats in the last round).? He might lose
when compared to every other candiate.

> The second claim of IRV that may be over-stated is that it eliminates
> the "spoiler problem."? While compared to our current voting method,
> IRV indeed solves the spoiler problem when independents or third
> parties run against two major parties.? However, concerns about
> "spoilers" could possibly resurface in some scenarios when there are
> three or more major parties.? But none of those scenarios have appeared
> in practice in those countries that use IRV and have more than two
> major parties.

In Australia, IRV results in an effective 2 party system.? However, they 
have more than 2 parties in the their Senate.

> As Arrow's Impossibility Theorem shows, it is impossible to invent a
> perfect voting method, as reasonable and desirable features that one
> would want in a voting method are mutually exclusive.

It doesn't mean that you can't compare methods to each other.

As the Yee diagrams show, IRV favours partisan candidates.?? You
win by getting lots of first choices.? It doesn't elect compromise 
candidates.

In effect, one block of voters gets their first choice and the other
block gets a candidate they hate.

Wouldn't it be better to have a compromise candidate that most
of the voters like, even if nobody gets their favourite ?

> IRV does better
> than most in real world experience, and virtually all elections methods
> experts agree it is superior to plurality elections we use currently.

That is a pretty low bar.? Plurality is a horrible system.


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