[EM] James: Your Range-Voting comments

[MIKE OSSIPOFF]

James--

You wrote:

Range voting is neither a majority rule method...

I reply:

That depends on what you mean by a majority-rule method. You define it below 
as a Smith-Criterion method, but you mustn't expect others to share that 
definition. Range-Voting, which I call CR, meets WDSC, which says:

If a majority of all the voters prefer X to Y, they should have a way of 
voting that ensures that Y won't win, without any member of that majority 
voting a less-liked candidate over a more-liked one.

[end of WDSC definition]

In most any method a majority has the power to make some pariticular 
candidate lose. In CR (including Approval) they can do that without 
reversing a sincere preference.

When a majority can easily nsure the defeat of a candidate, they can enforce 
majority rule. CR is a majority-rule method by that reasonable standard.

You continued:

Therefore, its
applications are very limited.

How do you justify the claim that the applications of methods that don't 
meet the Smith Criterion are very limited?

You continued:

Let's say that our voting scenario is a large group of people choosing an
executive (e.g. a mayor or president), and there is enough at stake that
people cannot be relied upon to vote sincerely.

I don't think that range voting should be used for this scenario. Why not?
Because it is not a majority rule system. It is possible for a candidate
to win in range voting even if they are the last choice of 99% of the
voters. Unlikely, but mathematically true.

I reply:

But nothing prevents you from voting strategically to prevent that. If you 
choose to rate sincerely, it's because you choose to accept the consequent 
loss of strategic power.

The ridiculously unlikely scenario that you worry about shouldn't distract 
you from the tremendous benefit of having CR instead of IRV or Plurality.


You continued:

In contentious executive elections, I think that we should stick to
majority rule methods. What is my operational definition of majority rule?
The winner should be a member of the minimal dominant set (aka GeTChA or
Smith). A weaker definition would be the mutual majority criterion. Range
voting passes neither of these criteria

I reply:

You haven't told us why you consider the Smith Criterion necessary.

MMC is good, but much benefit can be gained without it. You want everything. 
I've already said that the best rank methods, the wv Condorcet versions, 
offer additional criterion compliances that are desirable. You need to 
understand the difference between everything and enough.

You continued:

, and so I say it has no claim on
being a majority rule method.

I reply:

...as you define that term.

As for considerations other than majority rule:

As I said, sometimes CR will maximize SU when Condorcet or Cardinal Pairwise 
wouldn't. Sometimes the reverse is true.

You continued:

In some non-contentious election
scenarios, perhaps it can be. But in a contentious election, it is not. If
a Condorcet winner is not elected, it does not necessarily mean that
another candidate had a higher utility. More likely, it means that
supporters of the other candidate pulled off a successful strategy. The
interpersonal utility comparison aspect of range voting is just too easy
to hijack for strategic purposes, so that it essentially becomes
meaningless in a contentious election.

I reply:

Not at all. As I said, you can vote strategically in CR if you choose to,  
to protect the CW &/or majority rule.

You continued:

If one is concerned about the tyranny of the majority, range voting is not
the answer, because a well-coordinated majority can still guarantee
victory for their candidate of choice. [without reversing a sincere 
preference]

I reply:

And yet you say that CR isn't a majority method :-)

Mike Ossipoff

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