On Dec 31, 2004, at 7:00 PM, MIKE OSSIPOFF wrote:
Someone wrote:
That'd be me.
Being able to express ratings on a ballot is more expressive than only being able to express rankings. I think more expressive is a good thing.
On the back end, we could silently collapse the ratings into rankings by sorting the candidates, then apply Condorcet, IRV, etc.
I reply:
Sillently? Secretly? Letting people think they're voting ratings, and then counting them as rankings doesn't seem quite right.
Ah, um, "could" not "should" in most cases. One hypothetical reason to do it is if all the computers die and a hand count is needed. It might be the best thing to fall back and do a Condorcet hand count on ratings ballots.
You continued:
Straight rating summation is vulnerable to strategic voting. Perhaps in this study people voted honestly because it obviously didn't matter and so there was no incentive to vote strategically. In a real election the stakes would be higher.
I reply:
Do you know of a nonprobablilistsic methods that isn't vulnerable to strategy, that doesn't sometimes give incentive for strategy? If so, congratulations--you've proved Gibbard & Satterthwaite wrong.
I was just considering the zero-info strategy of maximizing and minimizing your ratings, degenerating to the Approval ballot. I think we can do better than that. I think "Instant Runoff Normalized Ratings" (IRNR) does better.
Seriously, all nonprobabilistic methods can have strategy incentive. One chooses which method's strategy incentive one wants. Some methods minimize it. For instance, Approval & Range-Voting (also called CR), never give anyone any incentive to vote someone over their favorite. No other nonprobabilistic method can make that claim.
Right. I choose "maximize social utility", "be fair to all voters", "encourage honest voting" (also, dishonest/strategic voting decreases social utility because if successful some victorious minority is happier while the majority suffers). Sorry if those goals are too fuzzy to be amenable to proof.
I also defined WDSC in my previous post. Approval, CR, and wv Condorcet meet it.
If a majority of all the voters prefer X to Y, then 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.
I think IRNR has this. I think IRNR is a strict improvement on straight Cardinal Rating summation, except for the computational burden.
Brian Olson http://bolson.org/
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