[EM] Kevin's other posting on votes-only criteria vs preference criteria.

[MIKE OSSIPOFF]

Kevin:

You said:

In practice [preference-mentioning criteria] usually have to be translated into votes-only criteria in order to figure out how to use or test them.

[endquote]

So what? Regardless of your procedure for applying the criteria, my criteria apply to all methods. Votes-only criteria often
do not, unless you say that Plurality passes Condorcet's criterion.

You continued:

>Well, in my mind a votes-only criterion is independent.

[endquote]

Independent of what? Either you stipulate that Condorcet's Criterion applies only to certain methods and not
to others, or CC gives results that are not as you or anyone else intend.

You continued:

Usually the two versions aren't quite equivalent or can't be easily proven to be equivalent.

[endquote]

Of course they're not equivalent. Preference criteria are universally-applicable.


You continued:

>I think part of the disagreement on this issue is based on who the audience is.

[endquote]

Irrelevant.

You continued:

On this list we don't generally have problems with most people using an implied Woodall-ish conception of methods and criteria.

[endquote]

That fact that it can be guessed what someone means when using those votes-only criteria doesn't answer my
criticisms of them.

You continue:

If someone wanted to argue that FPP actually does satisfy Condorcet we would just tell them they're doing it wrong

[endquote]

You could...and you'd be incorrect thereby.

If there is something wrong with how I interpreted votes-only Condorcet's Criterion, for instance,
when saying that Plurality meets CC, then I invite you to say what is wrong with that interpretation of CC.

Tell us how you define CC, minimal defense, and Majority for Solid Coalitions, without mentioning
preference. And then tell what's wrong with the interpretation of those criteria whereby Plurality meets
them.



You continue:


no big deal. Mike seems to be paranoid about people understanding criteria contrary to their original intention.

[endquote]

Is that what I said? I thought that I merely said that Plurality meets those criteria.

Oh yes, I did also say that your votes-only criteria often rule contrary to your intention. That makes nonsense out
of them and their use.

You continue:

>
>The inconvenient thing about e.g. SDSC is mostly the "should have a way of voting" wording.

[endquote]

How is that inconvenient? It sounds to me as if the meaning is quite plain. 

If a majority prefer x to y, 
then there should be a way of voting whereby that majority can vote that will insure that
 y won't win, without any member of that majority voting a less-liked candidate equal to or over a more-liked one. 
(other than equal-bottom-ranking them).

The use of the word "should" is commonly used on EM as an expression of the criterion's requirement for a method to 
meet the criterion. Is that what you're objecting to. I suppose I could have said, "A method meets SDSC if..."

...or divided the criterion text into "premise" and "requirement" as I did with CD.


You continue:

In practice this "way of voting" is almost always truncation 

It typically requires voting x above bottom, but not y.

You continue:

(which definitely is possible to define within Mike's scheme, as he doesn't consider truncation of two candidates to be voting them equal).

[endquote]

For some time I've been including that exception in the criterion's wording.

You continued:

>I wonder if SDSC can really be seamlessly applied to any ballot format though. Mike seems to assume it is unambiguous what it means to vote a candidate above or equal to or below another candidate. 

[endquote]

I defined that some years ago. Someone else suggested a much simpler definition, which I posted today. I agreed that that definition
was briefer, and that it was fine with me till such time as someone found a problem with it.

If it can be shown that you've found such a problem, then I'll discard that briefer definition, and return to the use of my
longer definition, the one that speaks, more generally, of an election with arbitrarily many voters and candidates.

You continue:

If he has a definition for these I imagine it's based on some very specific test that wouldn't necessarily reflect general method behavior.

[endquote]

See the definition that I posted today.

You continued:

For example, what if under some method the majority preferring A to B can make B lose by ranking B top? 

[endquote]

Let's say that that "ranking x higher than y" means that you write that candidate's name closer to the "top" of a piece of paper or the top of your computer screen, and that "ranking B top" means ranking B over everyone who isn't ranked as B is.

Then, in your questionably-proposable method, and by the definition that I posted today, ranking B, but not A, at top
qualifies as voting A over B, if that would defeat B even if you were the only voter and A & B were the only candidates.

If not, then we'd need to know more about the method that you're hinting at but not specifying.

You continue:

One could say (see definition below) that this is no good, because B is being ranked "over" A. But how do we know whether that's "over"? 

[endquote]

We know that because of how I defined "ranking x at top", above in this posting.

You continue:

Based on this one very counterintuitive result, it doesn't look like "over."

[endquote]

Well, you're the one (not quite) specifying that method. Don't attribute its irrationality to me.

You haven't shown that it makes a problem for my definitions.

You continue:

>What if voters can vote cycles? What if they put candidates in color-coded buckets and the outcome is determined by even vs. odd vote counts?

My definition of voting one candidate over another has nothing to do with any particular balloting format or count rule. 

Again, you'd need to be more clear with us regarding the method that you want to specify, before it and its consequences can be addressed.

You continue:

I think at some point, any criterion scheme has to say "use your head, you know what I'm trying to say," and where it says that is mostly a matter of taste.

[endquote]

Saying that you think that isn't the same as demonstrating it. If you want to claim that no criterion can be defined so that,
unambiguously, by its stated meaning, every reasonable method passes or fails it, then the burden is on you to demonstrate that.

Until you do, saying, "You know what I mean", doesn't adequately substitute for saying what you mean.


You continue:

>For reference, this is SDSC:

>If a majority of all the voters prefer A to B, then they should have a way of voting that will ensure that B won't win, without any member of that majority voting a less-liked candidate equal to or over a more-liked candidate.

[endquote]

Correct, except I have added to that wording "...other than ranking them both at bottom."

Not many methods meet SDSC. ABucklin and MDD,ABucklin do.

But difficultly-attainable criteria are useful for describing advantages offered by only a few methods.

1CM is attainable by more methods.


Mike Ossipoff


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