One kind of SODA strategy which I didn't discuss is candidate preference-declaration strategy aimed, not at directly attaining a better result, but at attracting votes. This would basically take two forms: established candidates truncating upstarts to try to minimize their importance, and a candidate altering their true preference order to better conform to some important fraction (probably the majority) of their voters. In both cases, these phenomena would tend to have a "bandwagon effect" which is arguably socially beneficial - minimizing the chances that a weak Condorcet winner will win the election, while strengthening the margin of true Condorcet winners. So I'm not worried about this sort of strategy being a problem.
Jameson 2011/12/15 Jameson Quinn <[email protected]> > > > 2011/12/15 Andrew Myers <[email protected]> > >> On 7/22/64 2:59 PM, Andy Jennings wrote: >> >>> 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. >>> >> I will repeat what I've written before: >> >> > I have to agree. SODA to me seems quite complex. It appears to pose >> difficult strategic decisions for candidates and even for voters. >> >> Thanks for the honest response. > > What do you think would help alleviate this largely-false appearance? > Voter strategy is limited to a few cases: > > 1. Correct approval strategy in case your favorite candidate's preferences > differ significantly from yours. People on this list understand approval > strategy; in my opinion, it's not ideal, but it's no worse than plurality > strategy, which most people tolerate. And I estimate that perhaps a third > or fewer voters will differ significantly from their favorite candidates. > If "significantly" only counts differences in the order between the two > frontrunner candidates, that kind of number makes sense. > > 2. Attempts at "chicken" strategy in a few cases. In the classic A+B vs C > case, such strategy can only work if C has no preference between A and B. > (Under one rule variant of SODA, even an honest preference that wasn't > predeclared would be sufficient to avoid a chicken dilemma). Note that, > unlike in approval/Range/MJ, the only way a chicken strategy can work for A > is by making it impossible for B to win the election; chicken strategy is > *always* either ineffective or dangerous. So it seems to me that in SODA, > unlike those systems, there is no slippery slope to a chicken dilemma. > > As for candidate strategy, that comes in two flavors: > > 1. Preference declaration strategies. Again, these mainly come down to > chicken strategies, and there are several restraints even on such > strategies. If A truncates B, B can retaliate; this should keep it from > happening unless A is clearly a second-string candidate, in which case it > may be a good thing. Also, C could intervene to avoid the dilemma. > > 2. Post-election strategy. This is a sequential, perfect-information game; > there's a single optimal strategy, and in any real election it's pretty > easy to calculate. (I can imagine artificially-balanced situations with > dozens or hundreds of candidates which might be NP-hard; but in real life, > it basically comes down to finding the delegated CW). > > Also note that journalists would quickly work out and publish the optimal > strategy and all plausible variations thereof, so the candidates would not > have to work it out on their own. > > So, I can't quite give a blanket denial that strategy matters, but I can > give a qualified one: in real life SODA elections, it is not worth worrying > about strategy. Having read the above, can you see any way I could say that > better? I want to be able to allay this concern; strategy issues are an > outstanding strength of SODA, not a weakness. > > Jameson >
---- Election-Methods mailing list - see http://electorama.com/em for list info
