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Show HN: RankedVote – SurveyMonkey but focused on ranked-choice voting

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Re: Show HN: RankedVote – SurveyMonkey but focused on ranked-choice voting

#271

Post by crazygringo »

achr2 wrote: post #149
lucasmullens wrote: post #93

Earlier quoted context omitted.

> If it's a close three-way election, you might cause your favorite candidate to lose by ranking them first. Could you explain that? I can't think of a situation where putting the candidate I want to win as #1 would cause them to lose. Ranking other close candidates as #2/#3 could cause my #1 to lose, but I don't think voting for someone as #1 alone would possibly harm them.

Let's say you have three candidates A, B, C. A is left, B is center, C is right leaning. Polling shows that voters are leaning: - 15% BAC - 15% BCA - 25% ABC - 45% CBA If everyone voted as they desired, then the instant runoff would be between B and C, with B winning with 55% of votes. If a subset of C voters instead strategically vote ACB (6%), this would change the runoff to be between A & C, with C winning 60%.

And just to be clear, this makes sense.

Because the relevant fact here isn't that some CBA voters put A at the front (ACB). It's that they moved B from 2nd to 3rd. So of course, that lessens support for B, so B no longer wins.

People seem to present this as a flaw, when it's reflecting actual changes in voting. And this is basically impossible to do so strategically, because nobody has this level of accurate detail prior to the election.

Re: Show HN: RankedVote – SurveyMonkey but focused on ranked-choice voting

#272

Post by naniwaduni »

dane-pgp wrote: post #217
garaetjjte wrote: post #156

Earlier quoted context omitted.

>see: Arrow's impossibility theorem Arrow's theorem only applies to ranked systems. That said, cardinal systems are still susceptible to strategic voting (Gibbard's theorem)

Thank you for pointing out how overused "Arrow's impossibility theorem" is as an argument against all voting systems (and therefore often as an argument against all reforms to the current near-worst possible voting system). I would go further and be somewhat dismissive even of "Gibbard's theorem", since it only shows that an insincere vote can strategically produce a better outcome for a voter if they can identify wh…

> I would go further and be somewhat dismissive even of "Gibbard's theorem", since it only shows that an insincere vote can strategically produce a better outcome for a voter if they can identify what that that vote should be, and if they are one of the voters for whom such a strategy is available.

Gibbard's theorem is even weaker than that. It only assures the constructibility of vote sets for which the right "final" votes to achieve a particular outcome are distinct. It does not guarantee that there are any insincere votes which perform better than a sincere vote!

Optimal strategic approval voting with a strict ordering is always a choice between sincere votes, in fact (since adding a vote for a strictly more preferred candidate never hurts your preferences, you can always find a sincere vote which performs better than an insincere strategic vote by additionally voting for all candidates more preferred than the least preferred candidate on the strategic vote).

Re: Show HN: RankedVote – SurveyMonkey but focused on ranked-choice voting

#273

Post by crazygringo »

elihu wrote: post #82
godelski wrote: post #57

Earlier quoted context omitted.

You don't think normal people can understand: "Rate this candidate from 0 to 5 stars?" If so, we really need to rethink a lot of how we ask for people's opinions, because this is probably the most common way.

The problem with RCV is there's a big difference between giving an honest opinion and voting tactically. In RCV it's safe to put your first choice first if either they're an overwhelming favorite to win, or they're so weak they're sure to get eliminated right away. If it's a close three-way election, you might cause your favorite candidate to lose by ranking them first. It's hard to develop any kind of intuition arou…

> you might cause your favorite candidate to lose by ranking them first

That's a flawed characterization that keeps getting repeated.

As I explain in another comment below, in theory you could get your favorite candidate to win by further downranking the candidate who would otherwise win. One way of accomplishing that is to move other candidates up higher above your actual preferred candidate.

But in reality, there's no way to know what the exact precise vote breakdowns will be, so voting strategically (lying about your preferences) is impossible in a practical sense. There's no intuition to develop -- just vote your preferences.

Re: Show HN: RankedVote – SurveyMonkey but focused on ranked-choice voting

#274

Post by naniwaduni »

godelski wrote: post #184
bombcar wrote: post #150

Earlier quoted context omitted.

I wonder if fixing the "strong case" spoiler actually is NOT what some "spoiler voters" would want, simply BECAUSE they want to spoil for the other party to try to move that party toward where they want it to be.

Probably. But I don't think the public really wants their voting systems to be highly vulnerable to strategic voting. That does just give elites an edge and ends up with less equitable representation. (strategies exist for ALL voting systems. But not all strategies are equally as bad)

Also, not all "strategies" fit people's intuitive notion of "strategy", which is colored by FPTP having a really glaringly awful strategic incentive for dishonest voting.

Re: Show HN: RankedVote – SurveyMonkey but focused on ranked-choice voting

#275

Post by crazygringo »

gamegoblin wrote: post #81
godelski wrote: post #71

Earlier quoted context omitted.

> That said, things like Approval have the opposite problem, in which moderates are given an advantage (some approval people will say this is a feature, not a bug). This is a weird way to say that representing the population is a bug. Your example election would be a compelling argument if population preference was more of a multimodal distribution rather than closer to a unimodal distribution. Despite the US's curre…

To be clear, I personally prefer approval to IRV. But raw approval gives undue advantage to moderates. Approval-to-runoff being clearly superior than raw approval, for this reason. And STAR being a little bit better than that. The RCV people's main criticism of Approval is that it doesn't allow you to express different levels of support, and they aren't totally wrong (even though their preferred mechanism of IRV does…

> I think (without data, happy to be proven wrong) that the US population is fairly strongly bimodal on most issues. Many issues that people care a lot about (for better or worse...) have two clear centers of gravity,

We'll you'll be happy then! :)

Because this is commonly believed but actually totally untrue. There's an entire book about it, "Culture War? The Myth of a Polarized America" by Morris P. Fiorina.

The upshot is basically that if you ask people binary yes/no questions (or binary left/right votes), the population appears divided, bimodal. But whenever you give a sliding scale in surveys, it becomes abundantly clear that the population is centrist -- unimodal. Even for gun control and abortion, the most hot-button issues.

Re: Show HN: RankedVote – SurveyMonkey but focused on ranked-choice voting

#276

Post by crazygringo »

notriddle wrote: post #157
JTbane wrote: post #147

Earlier quoted context omitted.

STAR voting can be easily gamed- tell your supporters "vote MAX for me and 0 for everyone else". Anyone who gives more than a 0 to their second choice candidate will hurt their first choice.

The only voting system that isn't "vulnerable" to bullet voting is FPTP, since it obligates you to bullet vote.

Huh? Ranked voting isn't vulnerable to bullet voting.

If you only rank a single candidate, there's zero benefit, you're just throwing away the rest of your vote. It's not giving that candidate any extra influence, the way it would in approval voting.

Re: Show HN: RankedVote – SurveyMonkey but focused on ranked-choice voting

#277

Post by crazygringo »

naniwaduni wrote: post #25
musingsole wrote: post #6

Earlier quoted context omitted.

Isn't approval voting just a signified form of Ranked Choice Voting -- one without prioritization? So the strength of RCV would then be more built in tie-breaking.

No. Approval voting is actually a minimized score voting system, and although intuitively a two-point feels like this should convey less information, the way the aggregation rule works (straight addition—or specifically in the approval voting case, tallying), you're actually extracting significantly more information out of a set of approval votes than you would from a ranked choice vote. To put it another way: given…

> When selecting for among three options, there are seven unique approval votes (the all marked/unmarked votes, expressing no preference, are equivalent), and only six ranked unique choice votes.

No, they're both six. There are 8 unique approval votes (2^3) but two are thrown out -- the all-marked and all-unmarked, so you're left with 6, same as ranked. RCV and approval absolutely do convey equivalent information in the case of three candidates.

I don't know where you're getting seven from.

Re: Show HN: RankedVote – SurveyMonkey but focused on ranked-choice voting

#278

Post by garaetjjte »

naniwaduni wrote: post #269
garaetjjte wrote: post #156

Earlier quoted context omitted.

>see: Arrow's impossibility theorem Arrow's theorem only applies to ranked systems. That said, cardinal systems are still susceptible to strategic voting (Gibbard's theorem)

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 ma…

>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.

Re: Show HN: RankedVote – SurveyMonkey but focused on ranked-choice voting

#279

Post by crazygringo »

naniwaduni wrote: post #262
crazygringo wrote: post #53

Earlier quoted context omitted.

Ranked choice absolutely conveys more information than approval. It's not as much as score voting, but it's mathematically false to say it's the same amount as approval. Among five candidates, approval would be 2^5-2=30 possibilities (almost 5 bits of information, assuming you can't approve/disapprove all because that's the same as not voting), while ranked choice would be 5!=120 possibilities (almost 7 bits of infor…

> Ranked choice absolutely conveys more information than approval. It's not as much as score voting, but it's mathematically false to say it's the same amount as approval. Among five candidates, approval would be 2^5-2=30 possibilities (almost 5 bits of information, assuming you can't approve/disapprove all because that's the same as not voting), while ranked choice would be 5!=120 possibilities (almost 7 bits of inf…

> This is a common intuition trap, but it's wrong.

I respectfully disagree. Yes it's true that jumping to lots of information with score voting doesn't produce an equivalent increase of meaningful information and that information is eaten by the aggregation technique, but I would argue that's not the case with ranked voting.

In the larger practical sense, yes there is a good argument to be made for approval voting if everybody voted honestly and gradations in preference strength were truly "dithered" relatively accurately among the population in a way that approval voting could "recover" the actual score-like preferences in aggregate. But the reality is that approval voting is easily subject to bullet voting manipulation, which destroys all of the information that it would otherwise contain in theory.

So in the real world, I submit that ranked voting ends up conveying more information that actually gets used, because there's more incentive to vote honestly.

> > And individuals don't have intransitive preferences, only populations can. (Assuming mental competence.)

> That's one hell of a bad assumption.

I assume you're just joking. Because yes while we can joke "hur hur people are dumb", if you're not taking people's votes seriously then what are we even doing? Every mathematical model must assume that individual's preferences are transitive, or we'd go mad.

Re: Show HN: RankedVote – SurveyMonkey but focused on ranked-choice voting

#280

Post by naniwaduni »

garaetjjte wrote: post #278
naniwaduni wrote: post #269

Earlier quoted context omitted.

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 ma…

>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…

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!

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