score voting is immune to the Gibbard-Satterthwaite theorem
I was basing this off the description in Wikipedia; please correct that entry if you think I was in error. As of this time it still explicitly states, “While the scope of this theorem is limited to ordinal voting, Gibbard’s theorem is more general, in that it deals with processes of collective decision that may not be ordinal: for example, voting systems where voters assign grades to candidates.”
any proportional method is subject to free riding strategy. And since this system is designed to be proportional across time as well as seats, free riding strategy would be absolutely pervasive, and I suspect it would take the form of deliberately voting for the craziest possible option.
What does that mean? If being the “craziest possible option” means it gets selected as the most preferred option regardless and has sharply bad outcomes that you secretly knew would happen, then having voted for it, you’re strictly worse off in future voting power than if you had voted against it. Alternatively, if it means that very few other voters vote for that option, then that option definitionally isn’t going to win, and so there is strictly nothing to gain in future voting power from having voted for it. So on the contrary, honest voting, as a strategy, dominates either interpretation of your suggested variant of a free rider strategy.
it’s a nonstarter politically
This is rich irony coming from Jameson Quinn himself. :D In any case, your comment here is certainly appreciated due to your expertise, even though I currently believe the comment was factually in error on both substantive points.
On Gibbard-Satterthwaite, you are wrong. Please read the original papers; Wikipedia is not definitive here. There is a sense in which the sentence you quote from Wikipedia is not quite wrong, but that sense is so limited that the conclusion you draw from it is not supported.
In terms of the “craziest possible option” strategy: people may deliberately vote for something they believe will not win in order to “build up” voting power for later. When they decided to actually spend this built-up power, they would not vote for something crazy. Insofar as this strategy artificially increases their overall voting power over that of other voters, it undermines the fairness of the system. And in the worst case, it could backfire by actually electing a crazy option. In case of backfire, this would obviously not be a rational strategy ex post, but I believe the collective risk of such failed rationality is unacceptably high.
As for the “rich irony” of me calling something a nonstarter politically: just this week, approval voting passed in Fargo; and STAR voting came within a few percent of passing in Lane County, OR. Last summer, thousands of people voted on the Hugo Awards which had been nominated through E Pluribus Hugo. In British Columbia, voters are currently deciding between four election methods, three of which are proportional and two to three of which have never been used. I personally played a meaningful role in each of these efforts, and a pivotal role in some cases. All of these are clearly far beyond “nonstarter politically”. So yes, I’m not afraid to tilt at windmills sometimes, but sometimes the windmills actually are giants, and sometimes the giants lose. I believe I’ve earned some right to express an opinion about when that might be, and when it might not.
I was basing this off the description in Wikipedia; please correct that entry if you think I was in error. As of this time it still explicitly states, “While the scope of this theorem is limited to ordinal voting, Gibbard’s theorem is more general, in that it deals with processes of collective decision that may not be ordinal: for example, voting systems where voters assign grades to candidates.”
What does that mean? If being the “craziest possible option” means it gets selected as the most preferred option regardless and has sharply bad outcomes that you secretly knew would happen, then having voted for it, you’re strictly worse off in future voting power than if you had voted against it. Alternatively, if it means that very few other voters vote for that option, then that option definitionally isn’t going to win, and so there is strictly nothing to gain in future voting power from having voted for it. So on the contrary, honest voting, as a strategy, dominates either interpretation of your suggested variant of a free rider strategy.
This is rich irony coming from Jameson Quinn himself. :D In any case, your comment here is certainly appreciated due to your expertise, even though I currently believe the comment was factually in error on both substantive points.
On Gibbard-Satterthwaite, you are wrong. Please read the original papers; Wikipedia is not definitive here. There is a sense in which the sentence you quote from Wikipedia is not quite wrong, but that sense is so limited that the conclusion you draw from it is not supported.
In terms of the “craziest possible option” strategy: people may deliberately vote for something they believe will not win in order to “build up” voting power for later. When they decided to actually spend this built-up power, they would not vote for something crazy. Insofar as this strategy artificially increases their overall voting power over that of other voters, it undermines the fairness of the system. And in the worst case, it could backfire by actually electing a crazy option. In case of backfire, this would obviously not be a rational strategy ex post, but I believe the collective risk of such failed rationality is unacceptably high.
As for the “rich irony” of me calling something a nonstarter politically: just this week, approval voting passed in Fargo; and STAR voting came within a few percent of passing in Lane County, OR. Last summer, thousands of people voted on the Hugo Awards which had been nominated through E Pluribus Hugo. In British Columbia, voters are currently deciding between four election methods, three of which are proportional and two to three of which have never been used. I personally played a meaningful role in each of these efforts, and a pivotal role in some cases. All of these are clearly far beyond “nonstarter politically”. So yes, I’m not afraid to tilt at windmills sometimes, but sometimes the windmills actually are giants, and sometimes the giants lose. I believe I’ve earned some right to express an opinion about when that might be, and when it might not.