Thanks, Andy, for the SODA endorsement. I agree with the advantages you list, but I would add the avoidance of the chicken dilemma (that is, the lack of either a self-reinforcing truncation incentive or hard-to-defend "mindreading"results that give a burial incentive) as an important advantage. Compromising favorite betrayal, truncation, and burial are the basic forms of strategy; and I don't know of any other system which is so resistant (and yet also resiliant) to all of these.
Jameson ps. I realize I'm repeating myself a bit, but as Andy said, an occasional plug for SODA is worthwhile. 2011/12/14 Andy Jennings <electi...@jenningsstory.com> > Jameson, > > Believe me, I'm on board with SODA. I think I, too, like it better than > LRV, but I'm still trying to get a handle on LRV to make sure. > > In my opinion (and my wording), SODA's advantages are: > > 1. The laziest possible voter, who just bullet votes for his favorite, is > still casting a (nearly?) optimal vote that is fair to him and to the rest > of society. > > 2. Voters can vote approval style, instead, if they want. > > 3. The only people who have to rank all the candidates are the candidates > themselves, who should be willing to do the work to come up with a full > honest ranking. Their ratings are public, so we can call them out if they > try to use turkey-raising or other dishonest strategies. > > 4. There is a "delegation" phase after the election where the candidates > can negotiate an outcome, but their ability to negotiate back-room deals is > severely limited because they have to use their pre-declared rankings and > they have to play in an order determined by the votes. In fact, there will > be a game-theory dominant equilibrium and the candidates will probably have > very little power to change the outcome. Chicken scenarios are avoided > because they know the play order, the other candidates' rankings, and > exactly how much voting weight each one has. > > 5. If there is some super-weak Condorcet winner that is totally unfit to > govern, then the others can indeed block him in the delegation phase. > > I don't see any huge theoretical downsides. Do others still have > reservations about SODA? I realize that some people may be opposed to > delegation, in principle. And others think delegable systems just don't > have a chance of getting implemented. So I think these debates about which > is the best voting system in the standard (non-delegable) model are still > useful. I also think it's useful for Jameson to inject a plug about SODA > every now and then. > > My main reservation about SODA at this point is that I see no practical > path to adoption. It would be perfect for a large primary, like the > current Republican presidential field, but there's no way to start at that > level. We have to start small. But for small political elections, > professional societies, open source decisions, elementary school elections > etc. it seems too complicated. I had a long discussion with a party > district chairman here. He's interested in alternative voting systems to > fill his party positions but skeptical of complexity. I don't even think > I've pitched him on SODA because he's still thinking about Approval Voting. > > And with SODA, you can't just run a straw poll to show it off like you can > with so many other voting systems. You need the participation of the > actual candidates to choose their rankings beforehand and to do their > delegation afterwards. > > I know we haven't traditionally discussed implementation strategy on this > list (though that has changed some recently), but if you see a good > strategy for SODA adoption, please tell. > > ~ Andy > > > > On Tue, Dec 13, 2011 at 6:55 PM, Jameson Quinn <jameson.qu...@gmail.com>wrote: > >> I believe that LRV (Least Resentment Voting) is indeed quite a clever >> solution to the chicken dilemma. But once more, I'd like to remind people >> that there is a way to solve the chicken dilemma without risking a victory >> by the plurality winner/condorcet loser. I'm speaking of course of SODA. >> >> First, SODA meets the FBC. In fact, in any 3-candidate scenario, and I >> believe in any 4-candidate one, it is strategically optimal to bullet vote >> for a candidate if you agree with their declared preferences. This ability, >> not just to vote your favorite equal-top, but unique-top, is not shared by >> any other method I know of. (Perhaps we could call this UFBC3, unique FBC >> for 3 candidates.) >> >> How does it do with chicken dilemma scenarios? For the following, I'll >> give honest ratings, then discuss the likely strategic implications under >> SODA. >> >> 40 C >> 25 A>B >> 35 B>A >> >> If this is the honest situation, then candidates A and B have every >> reason to find a way to include each other in their predeclared preference >> lists. These predeclared lists are made openly, and so one side cannot >> betray the other without giving the other side a chance to retaliate. The >> chance for retaliation will make betrayal a losing strategy. >> >> 40 C >> 25 A >> 35 B>A >> >> If the A camp is honestly indifferent between B and C, and candidate B >> finds this indifference credible, then B can still decide not to retaliate, >> that is, to ignore A's truncation and nonetheless declare a preference for >> A. This enables A to win without B spoiling the election. >> >> (Any single-round method which elects A here is subject to the chicken >> dilemma; electing B is, in my mind, crazy; and any method which elects C >> here has been spoiled by candidate B, and so encourages shenanigans of the >> republicans-funding-greens sort. Any method I know of except SODA fails in >> one of these ways.) >> >> 40 C >> 25 A>B >> 35 B >> >> This is like the above situation, but since A had no chance of winning >> anyway, they have even less of a motivation to retaliate against B, whether >> or not B's truncation is honest. >> >> 40 C>>A >> 25 A>>B >> 35 B>>A >> >> In this situation, it's difficult to say who's the "correct" winner; >> depending on the underlying utilities, it could easily be any of the three, >> so I'd have no problem with a method that elected any. Still, ideally a >> method would give similar results here as in the situations above, so that >> candidates and voters are not motivated to be conciliatory, rather than >> projecting an image of someone who's inclined to truncate. >> >> Strategically, it is in B's interest to truncate, to reduce the chance of >> 10 C>>A voters voting CA and thus giving A the all-important second move in >> the vote delegation stage. Then, candidate A will declare a preference for >> B, in order to present C with a credible threat. And candidate C will >> declare a preference for A to prevent B from winning. >> >> 40 C>>A??? >> 25 A>B >> 35 B>>A??? >> >> This is the "weak condorcet winner" situation. The question marks denote >> a "preference" for the dark-horse candidate A which would evaporate in a >> runoff, when people took a hard look at A without being distracted by the >> C/B rivalry. If that is the case, A should not win. And indeed, even if C >> predeclares a preference for A, when C is faced with the morning-after >> reality of the choice to throw the election to A or allow it to go to B, >> they have a chance to leave it with B if A is really such a bad candidate. >> Sure, C may prefer a weak winner who owes them a favor to a stronger >> opponent, and so elect A even if B would be socially-optimal; but at least >> SODA gives B a chance in this situation. Any Condorcet method would simply >> elect A and not look back. >> >> I think that the situations above show that SODA always allows honest >> truncation without a strategic penalty, but does not encourage strategic >> truncation. >> >> I know that some people on this list dislike SODA for its delegation. >> Obviously, I disagree. Consider: >> - SODA delegation is optional and eyes-open. Because of pre-declaration, >> you know what kinds of result your delegated vote could and could not >> promote, and if you don't like those results, you don't delegate. >> - SODA delegation allows results that seem to me to be obviously better >> than other methods in the above scenarios. >> - SODA delegation allows for unmatched simplicity from the average >> voter's perspective. If you like your favorite's declared preferences, just >> vote for them, and you're done. >> - SODA delegation allows significant minority candidates a moment of >> personal power, which they can use to extract (non-binding) promises before >> throwing their votes behind someone. I believe that this transitory moment >> of minority power is a healthy compromise between the stability and >> leadership in winner-take-all systems and the broader accommodation of >> minority interests in parliamentary systems. >> >> Of course, there are cases where SODA is not ideal. For instance, for a >> pre-election poll, SODA cannot be used unless the inter-candidate >> preferences can be somehow known or inferred. Still, I think SODA is >> overall a standout good method for most cases where high-stakes >> single-winner elections are appropriate. >> >> Jameson >> >> >
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