[EM] To Chris, about Range Voting

[MIKE OSSIPOFF]

Chris--

You wrote:

response to a post from  James Green-Armytage, Mike Ossipoff wrote
(Wed. Jan.5):

>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 particular 
>candidate lose. In CR (including Approval) they can do that without 
>reversing a sincere preference.
>
>When a majority can easily ensure the defeat of a candidate, they can 
>enforce majority rule. CR is a majority-rule method by that reasonable 
>standard.
>
CB: A slightly weaker version might  dispense with the "without any
member of that majority voting a less-liked
candidate over a more-liked one" qualification.  Is  your  "reasonable
standard" any more useful than that?

I reply:

Most definitely. Can you name a method that doesn't pass that weaker 
criterion?

Unless I'm mistaken on this, with any proposed method, a majority preferring 
X to Y has a way of voting that will make Y lose. But with Borda, that 
requires a knowledge of how the Y preferrers are voting, so Borda 
effectively fails. But with most any method, that majority can make Y lose. 
It's a question of what they have to do in order to accomplish that. I rate 
the methods by that. My criteria measure what it takes for a majority to 
make someone lose.

You continued:

If  a method  (like RV) that fails May's criterion/axiom

I reply:

I don't know what May's critrerion or axiom is, but I can predict that it 
probably won't be as important to me as the criteria that measure what a 
majority has to do in order to make someone lose. That's because I want to 
get rid of the lesser-of-2-evils problem, in which voters must abandon their 
favorite in order to make a greater-evil lose.

You continued:

, Majority
Favourite

II reply:

Majority favorite is usually defined in terms of voting rather than sincere 
preference:

Majority Favorite (as usuallly defined in terms of voting only):

If a candidate is voted as favorite (voted over every other candidate) by a 
majority of the voters,s that candidate should win.

[end of Majority Favorite definition]

For instance, Plurality is usually said to meet the Majority Criterion.

Yes, I agree that it's better to define the criteria in terms of sincere 
preferences, and that it would be good to have a  Majority Favorite version 
worded in terms of sincere preferences. But how would you word it?

You could say:

  If a majority of all the voters prefer X to Y then X should win.

that's no good, because no method meets it.

How about:

If a majority of the voters prefer X to Y, and vote sincerely, then X 
shouldn't win.

  This last summer I stated and named that criterion. I think it's 
desirable, and I described a method that meets it. It's a good method, but 
not very decisive, because it's possible for strategists to keep preventing 
ilt from electing anyone. For that reason I don't propose it.

So, unless someone gives us another version of Majority Favorite that is 
defined in terms of sincere preference, the Majority Favorite defined in 
terms of actual votes only is the only one that we have, and CR 
(Range-Voting) passes that one. So does Approval, since Approval is a CR 
version.

You continued:

  [If a method that fails Majority Favorite]
, and Majority Loser qualifies as a
"majority-rule method"; then can you tell us which methods don't?

Yes: Plurality, Instant Runoff, Borda, Margins Condorecet, and nearly all 
methods other than CR (including Approval), Condorcet(wv), Bucklin, ERIRV, 
and very few others.

Remember that "majority rule method" isn't my term. But I do have a set of 
majority defensive strategy criteria, so you can take your pick how much 
majorilty rule and strategy-freeness you want to insist on.

  I claim that the basic requirement for a method that deserves to be called 
a "majority rule method" is that it meet WDSC, whose definition you I gave, 
and which you copied in your reply.
WDSC is really the minimum requirement. CR (incluiding Approval) meets WDSC, 
and also meets FBC.



Brian Olson wrote (Fri.Jan 4):

>Of course, even a 1-100 scale can be so "abused". But if 99 people really 
>vote for their favorite with a "1", and the other guy with a "0", aren't 
>they effectively saying "I don't care (much)"?

I reply:

If the range is 0-100, then they're saying they care very little about the 
election.

You (Brian) continued:

Why should
>we be listening to their votes more than they want to be heard?

II reply:

Agreed. They're only voting one point of dilfference in a 100 point range 
election.

Mike Ossipoff

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