# [Election-Methods] RELEASE: Instant Runoff Voting (Chris Benham)

Terry Bouricius terryb at burlingtontelecom.net
Sun Jun 22 09:35:54 PDT 2008

```Ms. Dopp has requested a clearer example of how Range and Approval voting
can experience a spoiler scenario (through violation of the Independence
of Irrelevant Alternatives (IIA) Criterion). Although her inability to
follow Chris's logic led her to use extremely disrespectful language, I
will assume she was having a bad day and was just extremely frustrated.

Here is a simple example, that I hope she can follow...

How a voter scores a particular candidate (or whether the candidate is on
the positive or negative side of an approval cut-off) depends on what
other candidates the voter has to compare the candidate to.

If the voter thinks candidate A is okay, and B is horrible in a two way
race, the voter will likely score A as a 10 and B as a 0 (approve A and
not approve B). [Rather than insert an Approval Voting translation for
each point from here on I will just use a Range example, though the
dynamic is the same.]

If there are 100 voters and  55 prefer A>B and 45 B>A, this two-way race
could end with a total score of 550 for A (55 voters giving a 10 and 45
giving a 0) to 450 for B. Thus A is both the de facto majority choice as
well as the Range score winner.

Now comes the spoiler...What if candidate C decides to run as well? It
happens that a significant portion (let's say 25 out of the 55) of the
former A supporters who care most about issue X view candidate C as a
fantastically superior candidate to A or B (though they still prefer A
over B as well). It seems likely that many of these voters would feel the
need to reduce the score of ten they otherwise would give to A to make
room on the scale so they can indicate how superior C is to A. These 25
voters might now score the candidates as follows, A=5, B=0, and C=10. In
other words, the score that A now receives from some voters depends on
whether C has entered the race. The B supporters who generally don't care
much about issue X view C as just another version of A, so give this new
candidate a 0 as well. Under this entirely plausible scenario, with C in
the race, now the total scores might be A now only gets 425 (30 x 10 and
25 x 5), while B still gets 450 (45 x 10) and C gets 250 (25 x 10).

Thus C has "spoiled" the race for A. The entry of C caused B to go from a
loser to a winner.

The identical dynamic can be demonstrated for Approval Voting using voter
decisions about where to draw their approval cut-off line, once C enters
the race.

-Terry Bouricius
terryb at burlingtontelecom.net
(802) 864-8382

----- Original Message -----
From: "Kathy Dopp" <kathy.dopp at gmail.com>
To: <election-methods at lists.electorama.com>
Sent: Saturday, June 21, 2008 8:54 PM
Subject: Re: [Election-Methods] RELEASE: Instant Runoff Voting (Chris
Benham)

Chris,

You example clearly does not provide an example of approval voting
being subjected to the spoiler effect.

You managed to invent a really bad voting method (asking voters for
ratings and then converting their ratings to approval/disapproval by
your new voting method) and applied your method of conversions to your
own example, but it has nothing to do with either range or approval
voting methods.

Chris, This is the LAST time I will take any of my time to respond to
any of your emails since your emails either lack any logic or show
that you did not take the time to read and study either Abd ul's email
rebuttals of Fair Vote or the paper I wrote and I don't have time to
waste on annoying silliness.

On Sat, Jun 21, 2008 at 5:03 PM,  > Date: Sat, 21 Jun 2008 > Ok.
Suppose? the method is Approval, there are two candidates (A and B)
and the voters'
> utilities (sincere ratings on some fixed scale independent of the
> candidates) are:
> 40: A100, B98
> 25: A98,?? B1
> 35: B100, A1

OK. Then if this example is counted using approval voting by removing
the ratings for these voters, there is a TIE since 100% of voters
approve of both A and B.

>
> I assume that with just 2 candidates, all voters will simply approve the
> one they prefer to
> the other, to give the Approval result:
> 65: A
> 35: B

OK. This is a completely separate example of approval voting than your
first example.  BTW, in any election:

1.  voters have to make a choice on how they vote and cannot vote more
than one way in the same election using one ballot, and

2. the election has to be either conducted via one election method or
another - I.e. approval voting is analogous to rating candidates 0
(not approved) or 1 (approved), and so your above example shows ALL
candidates are approved if one tries to switch that to approval from
ratings.

In this example A wins.

> A wins. Now suppose that a third candidate (C) is introduced, and
> including this extra
> candidate the voters'? utilities are:
>
>
> 40: A100, B98, C1
> 25: C100, A98,?B1
> 35: B100, C98, A1

OK. In this example, removing the ratings to get approval voting
example (a third example related to neither of the first two, ALL
voters approve of A, B, and C and so A, B, and C are TIED again. It
seems like a pretty unlikely scenario, but then I suppose it is
possible.

> Now all the voters have one candidate they like very much, another they
> like nearly as much,
> and one they like very much less.? The voters best zero-information
> strategy is to all approve? 2
> candidates, to give the Approval ballots:
> 40: AB
> 25: CA
> 35: BC

OK, in THIS (yet another separate example of approval voting which is
not related to either of your prior examples in any way except by
dropping particular candidates from prior examples), B wins.

You are capable of understanding I hope that this example is entirely
different from your prior examples and that none of your examples are
of the same approval election?

If you are illogically claiming that these three entirely separate
examples are the same you must (I am guessing) be thinking in
backwards fashion that you can devine voter ratings from approval
ballots or that you can delusionally know how all voters would change
ratings to approval votes and vice-versa.

I.e. Certainly you must agree that:

1. voters must decide ONE way to cast their ONE ballot, and

2. it is not humanly possible to devine what ratings voters would give
to each candidate from looking at their approval voting ballots
because IF you are talking about APPROVAL voting, then there ARE NO
RATINGS, and you might agree that no one has superhuman powers to know
by looking at approval ballots, the ratings voters would give.

Chris, If you want to provide an example that makes a lick of sense
and does not assume that you can magically read all voters' minds, and
is logical and valid for EITHER approval or range voting which
exhibits the spoiler effect, then you must find an example that is
RANGE voting alone or an example which is APPROVAL voting that
exhibits the spoiler effect; or alternatively use only 0's and 1's to

Approval voting is analogous to giving a rating of 1 or 0, not the
example you gave.

So Chris, go back to the drawing board and eventually I believe that
you will discover that you can NOT come up with a valid example of
either approval or range voting that is susceptible to the spoiler
effect.

I.e. If you want to give an example where approval voting fails, use 1
or 0 for your approval/disapproval for candidates. Otherwise come up
with a range voting example, but your twisting all logic like you have
done in order to come up with a fake example is very annoying because
it is so stupid, and I am simply *not* going to respond to any more
illogical silliness on your part Chris; nor am I going to continue to
waste my time copying and pasting sentences from this list or from my
paper which you have not bothered to read.

Take the time to due your own research and reading and try again to
come up with a *valid* example and take the time to READ what Abd ul
and I have written, or stop wasting our time.

Kathy
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