Russ said:
What we have here, it seems to me, is confusion cause by a failure to distinguish between two fundamentally different classes of criteria. Consider the basic voting process. It starts with the voters' true preferences, then the votes are cast, then the votes are tallied and the winner is determined:
true preferences --> votes cast --> winner determined
Let's call the process represented by the first arrow the "voting strategy" and the process represented by the second the "tally rules."
I reply:
It's always been common knowledge on EM that strategy and count rules are 2 separate topics.
Russ continued:
All voting system criteria that I have ever seen, excluding those that originated with Mike, involve the tally rules. They consider only the votes cast and make no reference whatsoever to the true preferences of the voters.
I reply:
Perhaps. So what?
Russ continues:
At some point Mike came along and changed the paradigm fundamentally, probably without ever explaining that he was doing so.
I reply:
The fact that my criteria mention preferences was obvious enough without explaining. The difference between my criteria and the traditional ones was much trumpeted by Markus and Blake, so it was well-known on EM.
Russ continues:
Naturally, this causes confusion. To minimize the confusion, I suggest we distinguish between "normal" criteria and "Mike-style" criteria.
I reply:
I'll call them traditional criteria and preference criteria.
Russ continues:
I'll get to the value of Mike-style criteria shortly, but first let me say something about the old "Technical Evaluation" page at ElectionMethods.org. It had a set of 8 or 9 criteria and a compliance table for several major election methods.
Some of those criteria were Mike-style criteria and some were normal criteria. However, looking back at it, I see that we had the Condorcet criteria defined in terms of true preferences, with the stipulation that the voters voted "sincerely." Stipulating that the voters vote sincerely simply eliminates the voting strategy and essentially converts a Mike-style criterion to a normal criterion.
I reply:
No, the Condorcet's Criterion that was at the website at the technical evaluation page was a Mike style criterioni entirely. It referred to the CW (which you called the IDW, defined as I define the CW), and it stipulated sincere voting. Both the CW and sincere voting are defined by me in terms of preference, and were defined at your website in terms of preference.
Russ continues:
But it involves an unnecessary step that only confuses the matter. In other words, we had a normal criterion bollocksed up to make it look superficially like a Mike-style criterion.
I reply:
No, that Condoret's Criterion was thoroughly a Mike style criterion, for the reasons stated above.
Russ continues:
Mike-style criteria involve a model that normal criteria don't need.
I reply:
That's a safe statement, since traditional no-preference criteria don't need to mention preferences.
Russ continues:
They [Mike style criteria] need a model of voter preferences.
I reply:
Actually no. I've just told why they don't need a definition of preference, and they don't need the meaning of preference to be known, and they don't even need for preference to mean anything (though of course preference does mean something).
Russ continues:
What, then, is the value of Mike-style criteria? Voting strategy is a very important topic, of course, but I think that Mike just confuses the issue by trying to turn it into pass/fail criteria.
I reply:
Pass/Fail criteria are widely used in discussion of voting systems. They're the way to say something precise about voting systems.
Russ continues:
Take SFC, the "Strategy-Free Criterion":
"If an Ideal Democratic Winner (IDW) exists, and if a majority prefers the IDW to another candidate, then the other candidate should not win if that majority votes sincerely and no other voter falsifies any preferences."
I reply:
That's your wording, corrected by me so that it retains the meaning that I intended. But let me state it my way:
If no one falsifies a preference, and if a majority prefer the CW to candidate Y, and vote sincerely, then Y shouldn't win.
[end of SFC definition]
Russ continues:
(IDW was my name for the "sincere" Condorcet winner.) The only complying method is (a good variation of) Condorcet.
I reply:
The only well-known methods that comply with SFC are wv Condorcet methods.
Russ continues:
Now, what does this Mike-style criterion tell us? It tells us that a majority can use a strategy to thwart a minority.
I reply:
We're finding out that Russ hadn't a clue about the meaning of the criteria that were at his website.
Provided that no one falsifies a preference,
B loses without the CW>B voters doing other than voting sincerely. I don't call that a use of strategy by the CW>B voters. The point of the criterion is that, with complying methods, under the criterion's premise conditions, that majority needn't do other than vote sincerely, to make Y lose.
Russ continues:
So why, then, is it called the "Strategy-Free" criterion? It is called that because the strategy doesn't require any reversal of true preferences. But it *does* involve insincere truncation strategy
I reply:
Not at all. Russ just stated the criterion, and it didn't say that the members of that majority could keep Y from winning if that majority truncated. It said that if no one falsifies a preference, and if the majority who prefer the CW to Y vote sincerely, then Y won't win, with a complying method. The CW>Y voters needn't do other than rank sincerely. That's why it's called the Strategy-Free criterion.
Russ continues:
, which the criterion itself does not state. So the criterion name itself is misleading.
I replyi:
Russ has mislead himself by being unable to read what he's just copied.
Russ continues:
A more useful criterion is the normal (as opposed to Mike-style) criterion taken from Blake Cretney's website:
Name: Secret Preferences Criterion: SPC Application: Ranked ballots Definition: If alternative X wins, and some of the ballots are modified in their rankings below X, X must still win.
I reply:
Useful for what? As I always point out, it depends on what one wants from a voting system. My criteria measure for the goal of minimizing need for defensive strategy. Maybe Secret Preferences Criterion is useful for something else. Fine. Go for it. My criteria are explicitly written in terms of defensive strategy need. I don't claim that they should be useful to you if minimizing defensive strategy need isn't a goal of yours.
Russ continues:
Condorcet does not pass this criterion, which tells us that voters have incentive to truncate in some cases if not routinely. OK, then, lets determine when and how the voter should truncate rather than waste time making a useless criterion out of it.
I reply:
...but SFC & GSFC describe conditions under which, with complying methods, certain voters don't need truncation, or any other strategy, in order to defeat a candidate.
Russ continues:
Oh, by the way, did I mention that Mike-style criteria are pedantic?
I reply:
Maybe, by pedantic, Russ means that they have precise meaning, which tends to be lost when Russ tries to rewordl them.
Mike Ossipoff
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