[EM] Re: majority rule criteria--alternative nomenclature

[RLSuter at aol.com]

James,

I just don't think it is reasonable to call any method
but plurality itself a "plurality method" or to dismiss
approval voting as only marginally better than plurality.

I'm not a voting methods expert -- certainly much less
so than you and many other participants on this list. I'm
not even clear about the meaning of some of the terms you
use, including "mutual majority criterion" and "minimal
dominant set efficiency," which is why I can't address
some of your arguments.

Nevertheless, from everything I have read and figured out
on my own, approval is far better then plurality for all
voting situations (i.e., situations ranging from informal
groups needing to make quick decisions to presidential
elections), and in  some situations (especially small
informal groups needing to make quick decisions), approval
is far and away the best method -- indeed, the only very
good method that I'm aware of.

Now if you and Steven Brams were to debate approval voting
and you were to persuade all or most people attending the
debate that he has been a fool for advocating it all these
years, then I might change my mind. But I really doubt that
you could do that. My guess is that if you tried in such
a debate to argue that approval is only marginally better
than plurality, Brams would prove that it is you, not he,
who deserves to be called a fool.

I don't think you are a fool, but I do think it would
be foolish for you to continue treating approval voting
as dismissively as you have been and insisting that it
is only marginally better than plurality.

Ultimately, whether or not approval or other methods are
"majority" methods is a question of debatable definitions.
If approval voting would result in a Condorcet winner
95% of the time (just a guess, of course), that would be
sufficient for many people who are less perfectionistic
than you to regard it as a majority method.

Moreover, any process for making collective decisions,
including plurality voting and even some random selection
processes, could be considered a majority process if
it were chosen by a majority of voters and they agreed
beforehand to accept the outcome of the process.

In fact, I believe there are many situations where voter
approved random selection processes, especially ones
modified to insure proportional representation by qualified
people of major ethnic and other interest groups, would be
preferable to elections, no matter what voting method
were used. But that's a subject for another discussion.

-Ralph

---------------------------------------------------------
You wrote:

Ralph, you objected to the term "pseudomajority methods"
for non-majoritarian single-winner methods, on the grounds
that it was too derogatory. So, how about "plurality
methods" instead? This is appropriate for methods like
approval, range, and Borda, because what matter is who has
the highest cumulative score, rather than which candidates
are preferred by a majority over which other candidates. In
that case, I would update my single-winner classification
system as follows:

Criterion 1: If a majority of the electorate coordinates
their efforts, they can assure that a given candidate is
elected, or that another given candidate is not elected.
Criterion 2: Mutual majority criterion
Criterion 3: Condorcet efficiency
Criterion 4: Minimal dominant set (Smith, GeTChA) efficiency

Criterion 1 only: Plurality methods.
Criteria 1 and 2 only: Weak majority rule methods / mutual
majority methods.
Criteria 1, 2, and 3: Intermediate majority rule methods /
Condorcet methods
Criteria 1, 2, 3, and 4: Strong majority rule methods /
strong Condorcet methods / top cycle methods

Plurality methods: Plurality, approval, range voting, Borda
Mutual majority methods: single-winner STV
Condorcet methods: Minimax (aka SD, PC, etc.), Nanson,
Black, etc.
Strong Condorcet methods: ranked pairs, beatpath, river,
cardinal pairwise (assuming that a strong-majority base
method is used)