[EM] IRV's majority rule claim

[Richard Moore]

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