[EM] Explaining PR-STV

[Kathy Dopp]

On Sat, Aug 29, 2009 at 7:45 AM, Raph Frank<raphfrk at gmail.com> wrote:

>> To clarify, add..
>>
>> "All votes are equal"... *if* they are counted but some voters' never
>> have their 2nd or 3rd choices counted at all or before their 2nd or
>> 3rd choice candidates are eliminated
>
> I think we have a philosophical difference here (in fact, I know we do).
>
> You consider each individual ranking a vote.  However, I don't look at it that way.

It doesn't matter which way you look at it. I am happy to look at it
either way.  If you want to know what I think, then do the reality
check by asking me rather than trusting your imagination.

Looking at the 3 choices as parts of one whole vote does not change
the *truth* is that voters' "votes" are treated unequally.  Considered
as parts of a vote, some voters have only 1/3rd of their vote
considered, while others have 2/3rds or all of their entire vote
considered at all, or in a timely fashion.


>
> Each voter has exactly 1 vote.  This vote means that they can increase
> by 1 the vote total for any candidate.

True only in round #1, so entirely misleading unless the statement is qualified.

>
> The ranks are not votes, they are just instructions to the counting official on how you want your vote handled.

Yes, but most of the public has been fooled by the rhetoric of "Fair"
Vote into thinking that in IRV/STV:

1.  their 2nd choice candidate gets  a vote that could help their 2nd
choice candidate win whenever their 1st candidate loses, and that

2. majority favorite candidates win, and that

3. a vote for a candidate always helps, rather than hurts that
candidate's chances of winning, etc.

>
> If a candidate is eliminated, you instruct the counter to move you
> vote to the next highest candidate who is still running.
>
> Similarly, if a candidate is elected, you instruct the counter to move
> the part of your vote that they don't need to the next preference.

I fully understand the mechanics of the wholly unfair inequitable
IRV/STV counting methods whereby the supporters of the least popular
(first eliminated) candidates get to have their votes reallocated to
decide which other candidates are eliminated first and whereby the
voters of the early round winners in STV get to cast part of their
votes for their 2nd and/or 3rd choice candidates.



> It is true.  You won't be eliminated unless you have the least number
> of votes at that point.

Then, if you want to be remotely truthful, you need to add the clause
"in that round".



> Fair enough, I should have said most preferred candidate who has not
> been eliminated or elected.

and add "if any uneliminated candidates remain on your ballot at that
point" to give a more accurate picture of what happens to your choice
votes.  The only true claim that can be made is that a voters' 1st
choice candidate will be counted when that candidate is still in the
running. No promises about any later choices being counted can be made
unless that voters' 1st choice is the least popular candidate or in
STV is the most popular candidate that gets more votes than the quota.

>
>> 2. your vote for a losing candidate is for a losing candidate who does
>> not lose in the final elimination round, in which case your later
>> choices will never be considered.
>
> Right, there is up to 1 Droop quota of voters who don't get
> represented.  However, this is much better than potentially 49% of the
> voters not being represented in a single seat district.

In a single seat election, IRV can do much worse than that and elect a
candidate whom the majority of voters *opposes*.

>
>>> This reason for this rule is is so that you can safely give your first
>>> choice to your favourite even if he is a weak candidate.

You do not seem to understand that in IRV you can **never* give your
first choice vote to your favorite candidate unless you do not care if
your 2nd favorite candidate loses the election and your *least*
favorite candidate wins the election.

IRV has the *later no harm* criteria where a later candidate can never
hurt one's 1st choice vote, but a 1st choice vote can (and very often
does) hurt your 2nd choice and cause a majority-opposed candidate to
win.  This relates to the fact that IRV/STV does *not* solve the
spoiler problem of a nonwinning candidate who changes who wins the
election.

>>
>> This is a wholly, entirely, deceptively false statement. In IRV/STV
>> your first choice vote can always hurt the chances of your 2nd choice
>> candidate winning.
>
> Mostly, I don't think non-monotonicity is an issue with PR-STV (or at
> least the benefits outweigh that disadvantage)

I was not referring to non-monotonicity, yet another severe downside
of using IRV/STV counting methods.

>
> Would you prefer the simple version where the 5 candidates who
> received the most votes in the first round win?  That is monotonic, but is much less fair and gives more power to the parties.

Yes, I prefer that method any day as compared to IRV/STV methods, but
I believe that there are better Condorcet or range voting methods that
are fair and produce desirable results.


>
>> Yes. this would be more accurately rephrased "Be careful to vote for a
>> very very weak candidate first if you do not want your later more
>> popular candidates to lose."
>
> Actually, one of the strategies for increasing the power of your vote
> is to vote for a weak candidate first.


>
> Your later more popular candidate will not be eliminated before a weaker but preferred candidate.

True, but none of this negates the true fact that voting for a strong
candidate that makes it to the final counting rounds and then loses,
often means that your 2nd and later choices are not considered in a
timely fashion when they could help those candidates to win.

>
>>> 4) If you vote for a candidate who gets more votes than he needs, the
>>> surplus is transferred to your next choice.
>>
>> Again, this is only true in special situations similar to those
>> mentioned above for having your vote for a losing candidate
>> transferred.
>
> Ok, it is only transferred if you have indicated which candidate you
> want to transfer it to.

No. That is not what I said. It only gets transferred if your 2nd
choice candidate has not already been eliminated.

>
> I don't see how that is unreasonable.

Well you and I do have a philosophical difference because I believe
that voters have the rights to:

1. know that the effect of casting a vote for a candidate will be to
help, not hurt, that candidate's chances of winning, and to

2. have their own vote treated in the exact same equal manner as all
other voters' votes.

I.e. I believe in the rights granted by the US constitution and
federal case law to equal treatment under the law and that the right
to vote includes the right to know that the effect of a vote will be
positive for the candidate one votes for.

> Having said that, I would support decreasing the quota on the fly.

Exactly my point. In IRV/STV you *must* decrease the quota on the fly
or have another run-off election to fill all the seats.

> However, that is just making the method more complex for little
> benefit.

Oh so filling all the seats or actually following the statutes that
requires a particular quota is just a "little benefit"?

-- 

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 - 18 Flaws and 4 Benefits
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