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Gibbard's theorem implies "strategy" in a sense (your optimal strategy depends on distribution of other people's votes) which is much less nefarious than many p

Gibbard's theorem implies "strategy" in a sense (your optimal strategy depends on distribution of other people's votes) which is much less nefarious than many people's intuition on what "strategic voting" implies. When people think about strategic voting coming from a FPTP context, the strategy they're thinking of is putting in a dishonest vote for a non-preferred candidate because that provides a better chance at matching their preferences than an honest vote. This is not what Gibbard's theorem is about. Strategic voting in cardinal systems, for example, tends to look basically like dynamic range compression and at an individual level generally only "tiebreaks" between candidates that were otherwise fairly evenly matched, while the FPTP strategy of bullet voting a non-preferred candidate is just straight up bad for your preferences.

garaetjjte 4y ago
>putting in a dishonest vote for a non-preferred candidate because that provides a better chance at matching their preferences This still somewhat exists. For example, with score voting: preferences A>B>C but you really hate C, and he's leading in polls. It might be reasonable to "dishonestly" score B higher. This minimizes chances that C wins, and while it doesn't harm A it does decrease strength of your preference for A>B. "Dynamic range compression" is good way to put it, or maybe "ballot influence conservation": one ballot has fixed influence, and you can either spend it entirely on A/B>C or A>B/C, or any ratio in between.
- naniwaduni 4y ago
  Yeah, "dynamic range compression" on a score vote does feel a bit dishonest—kind of independently of whether it's actually "strategic", actually. Personally, this is a major factor in preferring approval over score vote, which requires someone who intuitively "feels", say, a 0.3/0.6/0.7 about candidates to either vote 0/0.75/1 to maximize their vote spread, or give more influence to people who do. Notice that this is not strategic in Gibbon's sense—it is always better to vote 0/0.75/1 than it is to vote 0.3/0.6/0.7—but it's probably more counterintuitive!

garaetjjte 4y ago

>putting in a dishonest vote for a non-preferred candidate because that provides a better chance at matching their preferences This still somewhat exists. For example, with score voting: preferences A>B>C but you really hate C, and he's leading in polls. It might be reasonable to "dishonestly" score B higher. This minimizes chances that C wins, and while it doesn't harm A it does decrease strength of your preference for A>B. "Dynamic range compression" is good way to put it, or maybe "ballot influence conservation": one ballot has fixed influence, and you can either spend it entirely on A/B>C or A>B/C, or any ratio in between.

naniwaduni 4y ago
Yeah, "dynamic range compression" on a score vote does feel a bit dishonest—kind of independently of whether it's actually "strategic", actually. Personally, this is a major factor in preferring approval over score vote, which requires someone who intuitively "feels", say, a 0.3/0.6/0.7 about candidates to either vote 0/0.75/1 to maximize their vote spread, or give more influence to people who do. Notice that this is not strategic in Gibbon's sense—it is always better to vote 0/0.75/1 than it is to vote 0.3/0.6/0.7—but it's probably more counterintuitive!