[EM] Approval Elections & Effective Weights

Martin Harper mcnh2 at cam.ac.uk
Wed Apr 11 07:15:20 PDT 2001

Replies mainly in the text.

One thing I will comment up front here - I answered Don's questions, and I shall
answer yours, later on in this post. It is customary to allow time for people to
answer your questions - patience, I am often told, is a virtue.

Craig Carey wrote:

> If there is a problem naming a nation that uses the [newly named]
> "Approval variant of the Block/Cumlative Vote" then perhaps a more
> thorough search is needed.

I'll keep calling it Approval, thanks.

Incidentally, you complain about me using the term "IRV" - you say:
> the so called 'IRV' method

I thought that this was the standard name: "Instant Runoff Voting", or "IRV". What
do you call it?

> Let's consider the failure of Mr Davison to restrict the election to be quite
> public election. Can the error be repaired. That might be a dead of a topic.
> Was Mr Davison thinking of public elections?

Sadly, my pet psychic was on holiday the day I answered Mr. Davison's question, so
I had no option but to answer the question he actually wrote, rather than what
might have been going on in his brain.

> The comment about voting machinery indicates that Mr Harper was perhaps thinking
> of large elections.

You'll note I said "voting machinery and/or education". In small elections some
education would be the appropriate way forward. One wouldn't need a lot - marking
an Approval ballot is no harder than marking a Plurality ballot. In large elections
one has the benefit of voting machinery too. I don't know what was going on in Mr.
Davison's brain - I was thinking of elections of all sizes.

> Are or are we not in some sort of close contact with the supremos of Approval
> variant advocacy?.

I'd have a hard job passing myself off as a supremo of anything, I've only been
discussing election methods for a few months, and I'm a programmer, not a
statistician or politician, by trade. But I do advocate Approval.

Actually, what I really want is some kind of Cardinal Ratings method which doesn't
suffer a strategic collapse. But so it goes.

> Never never divulges probability distributions.

I believe I specifically said that it was a uniform probability distribution. IE,
there was a 50% chance of there being one 'B' voter, and a 50% chance of there
being no 'B' voters.

> Unfortunately probabilities associated with utility theory are a well guarded
> secret.

You really ought to tell Blaise Pascal that - he invented them back in the
Rennaisance some time. By now, they're comparatively common knowledge - taught in
schools and such, and used to help make business decisions and suchlike under the
pseudonym of "Expected Value".

> The "effective weight" is defined by me so that it ends up with the meaning
> that people would think it ought have: it is the ratio x/y, where x is the
> number of FPTP votes that are required to offset y of another vote.

> A point
> I have not fully figured out is how to replace the reference FPTP votes with
> votes having more than one preference.

First of all, thank you for answering my question.

I think the key question is how one replaces the FPTP vote with the
Approval/Ranked/Dyadic Approval/Cardinal Ratings/whatever ballot that the election
method under test is using.

EG: As you know, Plurality (aka FPTP) has a spoiler problem, which IRV largely
eliminates. For example, a Nader supporter in the last USA election might vote Gore
in Plurality, to attempt to keep out Bush. In IRV, however, they don't need to
worry about that spoiler problem, so they can safely vote Nader>Gore instead. On
the other hand, a Gore supporter would vote Gore in Plurality, and Gore in IRV.

This is going to be the case in all methods: a FPTP vote for a candidate might be
translated to a number of possible votes in more advanced methods. How do you
intend to resolve this?
And finally.

Don wanted to know if Approval was used in any real elections, and I answered that
question. Don also wanted to have details of actual results, and I replied that I
didn't have those details, so he'd have to look for them himself. There is a
further question now: is/was Approval used in any public, country-wide, elections?

According to the same paper I shamelessly plagiarised last time for details of
elections to professional bodies like the IEEE:

> "In the former Soviet Union, many elections involved the presentation of a list
of candidates to the voters, and voters were only allowed to cross names off the
list: this system is equivalent to allowing the casting of approval votes (for the
candidates not crossed off)...... In 1991 Oregon conducted a public referendum
involving five alternatives using approval voting."

So here we have the former Soviet Union using "Disapproval", which is equivalent to
Approval, and Oregon using Approval for a public referendum. I do not know whether
there have been any public country-wide Approval elections since then - I've not
looked or particularly cared. As in my reply to the last question, I do not have
the results for any of the mentioned elections: primarily because I don't care.
Does that answer your question, Craig?


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