[EM] Get Real, Richard Moore:

I Like Irving donald at mich.com
Mon Apr 2 05:57:25 PDT 2001

- - - - - - - - - - - - - - - - - - - - - - - - - - - - 04/02/01
Mr Richard Moore,

You wrote:  "Why is the particular majority selected by IRV entitled to be
the majority that rules, when there are so many other possible majorities?"

Davison: Yes, you are correct, there are other possible majorities than D
11 of 17.  Had you ran one more runoff cycle you would have gotten a
majority of D 17 of 17,  but that is not what you had in mind was it?  You
are fishing for a majority that will elect one of the lowest three
candidates like A or B or C.
     In order to do that, you will need a different method.  Approval
Voting is currently in vogue on this EM list.  We should try that method
before it goes out of fashion.  Approval Voting will give the following
results to your example:
              17 A,   17 B,   17 C,   17 D,   17 E

     Opps, looks like Approval Voting is unable to give you a `better'
winner with a different majority.  In fact, Approval is useless, for it has
yielded a silly result.  That's Approval for you.

     Bucklin will give us: 17 A,  2 B,  3 C,  6 D,  6 E
     So, it is candidate A, the lowest candidate of top choices, that you
have determined shall win the election in your concocted example.  Why did
I not see that before, yes indeed, why not?

     What is wrong here is that Bucklin violates the Golden Rule of
Preferences, that is, later preferences are not to harm nor help earlier
preferences. The Bucklin solution is a clear case of lower choices helping
to defeat top choices.

     Besides, your example is unrealistic on three accounts.
     One, voters of the top two candidates, D and E, would not march
lockstep and vote for the same second choice A, and then the same third
choice B, etc.
     Two, few of the D and E voters would choose A or B as a second or
third choice when we consider that the voters of A and B chose D and E dead
last, the dislike would be mutual.
     Three, there is no reason for the voters of the two front running
candidates, D and E, to make any lower choices. Their two candidates are
head and shoulders above the three lowest candidates, it is of no interest
to these voters which of the three is to be the last candidate.

     A more realistic example would be:
        6 E,  1 ACBD,  2 BACD,  2 CABD,  6 D

   Irving: candidate D still wins with 11 of 17

 Approval: candidate D wins, 5 A,  5 B,  5 C,  11 D,  6 E

  Bucklin: candidate D wins, 5 A,  5 B,  5 C,  11 D,  6 E

Condorcet: candidate D wins all D pairings.

     The jury is in, candidate D is the winner, but we already knew that.
     You were merely hoping against hope that your bottom feeding candidate
would somehow win - it's not going to happen.  We will not allow you to
leverage one vote into a win.
     To see this, all you need to do is to `Get Real' Richard Moore.

Mr Davison

 ------------- Original Letter ----------
Date: Thu, 29 Mar 2001 22:51:36 -0800
From: Richard Moore <rmoore4 at home.com>
To: Election Methods <election-methods-list at eskimo.com>
Subject: [EM] IRV's majority rule claim

Consider the following case:

6    EABCD
1    ACBDE
2    BACDE
2    CABDE
6    DABCE

In IRV, after 3 rounds, you end up with

6    ED
1    DE
2    DE
2    DE
6    DE

so D beats E in the 4th round, 11 to 6.

The IRV proponents like to call this a majority victory for D. But
what do the majority of voters think of D? You have 6 voters who
ranked D last, and 5 who ranked D next to last. So 11 of 17
voters evidently think D is a poor candidate. Only 6 of 17 ranked
D among their top choices. That's how well IRV serves
majority rule.

The problem with the IRV proponents' claim for majority rule is
that they have assembled their majority only by eliminating many
of the preferences of that majority.

IRV would elect anchovies as a favorite food because a majority
of people like anchovies better than liver. (OK, some of you out
there may like one or both of those foods, but you get the idea.)

A population can be divided into a majority section and a minority
section many different ways. Why is the particular majority
selected by IRV entitled to be the majority that rules, when there
are so many other possible majorities?

I acknowledge it's possible that the 11 voters who preferred
some permutation of ABCD over E may actually have very
close ratings of those four. They could all despise E but just
be unable to agree on whom they want instead. But the IRV
proponents should similarly acknowledge the opposite
possibility, that 5 of the 11 dislike D almost as much as
they dislike E. IRV simply doesn't measure the strength of
preferences. And D and E could both be extremists. How can
the centrist voters in this scenario change their votes to
ensure a centrist candidate wins?

Even the voters who favor D or E would probably rather not
see this race come down to a contest between D and E,
because they know that if their choice loses, they will have
to endure a win by the most evil candidate on the ballot.
I know I would rather think we were choosing between
two of the best, rather than the leftovers of some pseudo-
random elimination process.

-- Richard

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