[EM] By their kind of preference, Approval & RV match Condorcet

[Dave Ketchum]

On Tue, 18 Oct 2005 01:47:26 +0000 MIKE OSSIPOFF wrote:

> 
> As I said, it's a matter of individual subjective choice, about which 
> kind of preference one wants to go by, and, as a result, whether one 
> preferes Condorcet, Approval or RV.
> 
> Here are 3 kinds of preference, which I'll define later:
> 
> 1. Bare preference (could also be called ordinary preference).
> 2. Emphatic preference.
> 3. Measured preference.
> 
> 1. Bare preference or ordinary preference is what we usually refer to 
> when we say that someone prefers X to Y. It could be that they _barely_ 
> prefer X to Y, hence the name. Bare preference is the kind that 
> Condorcet measures, and, as I said, it's the kind that we've usually 
> been talkling about in votilng system discussion.
> 
> 2. Emphatic preverence is what Approval measures. Do you prefer X to Y 
> enough that X>Y is important enough to make it one of the preferences 
> that you vote? Are X and Y on opposite sides of the most important or 
> significant division into sets of higher and lower merit?
> 
> 3. Measured preference is what RV measures. That's probably 
> self-explanatory. The rating difference that you vote among two 
> candidates is your measured preference between them.
> 
> In a posting some days ago I pointed out that, with pairwise-count, if 
> voting is sincere and more prefer X to Y than Y to X, then X will beat Y 
> pairwise.  And that, in Approval, if more people emphatically prefer X 
> to Y than Y to X, then Y can't win, because X will outpoll Y.
> 
> I pointed out that, in that way, by emphatic preference, Approval 
> matches what Condorcet does.


That is no more useful than measuring hair color, when the task depends on 
muscle.

For that matter and your measurements, does not Plurality land in the same 
ballpark?

> 
> Someone could say, "Yes, but not the criteria."  Yes the criteria too, 
> the emphatic preference version of them.
> 
> I'm not calling these actual criteria, because they haven't been written 
> so that they apply to all methods. I only mention them for showing 
> that,  by emphatic preference, Approval matches Condorcet, criteria and 
> all. At least the important criteria.
> 
> Condorcet's Criterion:
> 
> What if there is a candidate who pairwise beats every other candidate, 
> by emphatic preferences?
> S/he gets the highest vote total and wins.
> 
> SFC:
> 
> What if a majority of the voters emphatically prefer X to Y? Y can't 
> win, because X outpolls Y.
> 
> MMC:
> 
> If set of voters consisting of a majority of all the voters emphatically 
> prefer all the candidates in set S to the other candidates, then the 
> winner will come from S.
> 
> Obviously that goes for RV's measured preferences too.
> 
> That's why I say that, by emphatic preferences Approval matches 
> Condorcet. And that, by measured preferences, RV matches Condorcet.
> 
> Additionally RV and Approval have their own social optimization, which 
> has been discussed here.
> 
> It's just that, as an individual objective preference, I tend to prefer 
> going by ordinary preferences, and so I'm a Condorcetist, and I claim 
> that, by ordinary or bare preference, SSD is the ideal best for public 
> elections if voters make good judgements about who is good enough to 
> vote over their favorite, or if the greater-evils have been voted out of 
> the political system. (It's because those desirable conditions don't 
> obtain in our public political elections that, as a practical matter, I 
> prefer MDDA for public elections, and consider RV and maybe Approval to 
> be the best public proposals, when winnability is taken into account.
> 
> But, even under conditions where FBC wasn't needed, I'd gladly accept 
> Approval or RV for public political elections, if others wanted it, or 
> if feasibility considerations necessitated it. Likewise, in 
> organizations, I have no objection to Approval or RV if others prefer 
> them, or if they're more convenient.
> 
> Mike Ossipoff

-- 
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  Dave Ketchum   108 Halstead Ave, Owego, NY  13827-1708   607-687-5026
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