[EM] Why I think IRV isn't a serious alternative 1

[Kevin Venzke]

Hi,

--- En date de : Lun 1.12.08, Abd ul-Rahman Lomax <abd at lomaxdesign.com> a écrit :
I initially wrote:
> > Hello,
> > 
> > --- En date de : Mar 25.11.08, Abd ul-Rahman Lomax
> <abd at lomaxdesign.com> a écrit :
> > I don't understand how you reconcile the two ideas
> here. Range is
> > "objective" and "ideal because it's
> designed that way" based on the
> > idea that voters have internal utilities and, if they
> vote them exactly,
> > under Range voting, the best candidate according to
> overall utility
> > will be elected every time.


> This is the "relatively objective method of
> assessing" election outcome. When it's easy to
> determine, in a real situation, the absolute individual
> voter utilities, "fully sincere Range Voting"
> implements it as a method. That is, if the voters are
> honest, or if their "votes" are determined for
> them by some objective method -- such as a measurement of
> tax impact based on, say, the previous year's income tax
> return -- this obviously would produce an objective result
> that could be considered ideal. In real elections, of
> course, determining absolute, commensurable utilities may
> not be possible. (There are voting systems involving
> lotteries and real bets made by voters that should encourage
> the voting of absolute utilities, but these aren't being
> considered here.)

In your previous message you seemed content to say that voters can't
vote "accurately" under Range because they don't know how and because
the ratings have no inherent meaning.

I'm assuming we don't introduce external incentives into the election
method.

> In real elections, voter behavior will deviate from those
> "fully sincere" votes. (Fully sincere means
> disclosing true preference strength, within the resolution
> of the method.) It deviates from it for two reasons: (1)
> voters don't care to put that much effort into rating,
> it's easier to rank, generally, because it only involves
> pairwise comparisons; however, voters usually only have
> meaningful preferences between a few of the candidate pairs
> involved. And (2) voters are accustomed to elections being a
> choice, or a set of choices, and choices are normally made
> within a context that considers outcome probabilities where
> choice power is used to choose between realistic
> possibilities, not merely to compare the value of each
> outcome.

This seems pretty different from your explanation previously.

> So: How does Range, with realistic voting patterns, compare
> with other methods. Range does *not* produce zero regret. It
> produces relatively low regret. If fully sincere voting
> could be somehow guaranteed -- probably impossible -- it
> would always choose the ideal winner (within certain
> restrictions, basically normalization). So there are two
> deviations from the ideal. The first is from normalization,
> and the second is from strategic voting.
> 
> Range *with strategic voting* is better with respect to
> regret than any other method that has been simulated, to my
> knowledge.

If this is true it can only be by comparing strategic Range to strategic
(insert rank ballot method), which is at the mercy of Warren's 
understanding and implementation of rank ballot strategies.

> There is an exception: Top Two Runoff Range
> Voting beats Range. That's not surprising. It would
> detect and fix some of the deviations due to normalization
> and strategic voting.

I'm not sure what this method is but it sounds vulnerable to clones.

If you're open to introducing mechanisms to fix problems caused by Range
strategy, I wonder why you would keep it to just this.

> Now, to prevent the advantage that knowledgeable voters
> would have from being able to vote accurately, should we
> damage the outcome averaged over all voters?

How is it even clear that it would be damaged? You've presented an idea
of what people are doing when they go to vote, and trying to vote 
accurately wasn't part of it. People are making sincere, strategic 
decisions.

> This is the implication of the argument that we should
> prevent "strategic voting" as it applies to Range.
> 
> To be continued.

Ok.

Kevin Venzke