[HN Gopher] The user experience problems of quadratic voting
       ___________________________________________________________________
        
       The user experience problems of quadratic voting
        
       Author : timdaub
       Score  : 129 points
       Date   : 2022-03-27 18:08 UTC (2 days ago)
        
 (HTM) web link (timdaub.github.io)
 (TXT) w3m dump (timdaub.github.io)
        
       | captainmuon wrote:
       | I don't understand how quadatic voting can deal with collusion.
       | Say I want to give 4 credits to A, and a friend wants to give 4
       | credits to B. So each of us gives 2 votes to their preference.
       | But if we join together, we each give 2 credits to each option,
       | that is sqrt(2) votes. So each option gets 2*sqrt(2) ~= 2.8 votes
       | instead. So we are strongly incentived to found a party and to
       | pool our votes. I'm not sure this is what people intended.
       | 
       | It also seems to punish caring strongly for a certain issue,
       | whereas I wonder if that isn't maybe an indicator that you are
       | informed about a topic, and thus your vote should count more
       | rather than less?
        
         | ekelsen wrote:
         | Collusion is prevented in the same way that vote buying is
         | prevented now -- you can't verify how other people have voted.
         | This means that you could tell your friend you'll vote for B,
         | but actually still vote for A and A will get more votes.
         | 
         | Since you can't verify that collusion has worked, the best
         | strategy is to not do it.
        
           | samatman wrote:
           | I wouldn't be so quick to dismiss here.
           | 
           | Collusion in 'linear' voting loses the voter their preference
           | in exchange for some reward, double-dipping is a simple
           | defection.
           | 
           | GP is talking about personal force multiplication through
           | collaboration, it's win-win so you have a genuine prisoner's
           | dilemma. Being unable to verify cooperation doesn't mean it
           | won't happen in other ways.
           | 
           | I don't know that this is actually _bad_ just that a simple
           | comparison to linear votes doesn 't hold up.
        
             | ekelsen wrote:
             | Let's say we agree to cooperate because it's win-win. Then
             | I go into the voting booth, do I have any incentive _at
             | all_ to not vote for my preferences as opposed to yours?
             | No. Why would I not defect and gain more votes for my
             | preferred causes?
        
               | breuleux wrote:
               | Some people don't like lying about what they are doing,
               | even if they can't get caught. Small scale cooperation
               | between honest people would probably work for that
               | reason. On a large scale, it probably wouldn't be very
               | efficient, but insofar that both sides would defect or
               | cooperate at roughly the same rate, you would still
               | expect it to be somewhat beneficial if the cooperation
               | rate is nonzero (but maybe not enough to be worth the
               | trouble).
        
               | dane-pgp wrote:
               | > Some people don't like lying about what they are doing,
               | even if they can't get caught.
               | 
               | Unfortunately, some people _do_ like lying, or at least
               | they don 't mind it as much, and if you create a system
               | which rewards liars more than honest people, you
               | shouldn't be surprised if the liars end up winning _and_
               | you create more liars.
        
               | notahacker wrote:
               | In certain scenarios (bloc votes) the defection is fairly
               | obvious afterwards, so the standard conclusion that
               | always defecting is a bad strategy if the prisoner's
               | dilemma is iterated and [probable] defection can be
               | established over time applies.
               | 
               | The quadratic maths tends towards making the gains from
               | collusion very large, which means there is incentive not
               | to defect even if detection is uncertain.
               | 
               | And bloc votes and ballots which aren't necessarily
               | secret do represent some of the more plausible use cases
               | for quadratic voting (corporate governance)
        
               | comex wrote:
               | This is the same situation as prisoner's dilemma and has
               | the same possible answers. One is, as others have said,
               | that some people will choose honesty for personal moral
               | reasons. Another is superrationality:
               | 
               | https://en.wikipedia.org/wiki/Superrationality#Prisoner's
               | _di...
        
               | samatman wrote:
               | My "defects reliably when protected by incomplete
               | information" T-shirt is raising a lot of questions
               | already answered by my T-shirt?
        
             | lukifer wrote:
             | Preference collusion in linear voting isn't completely
             | unheard of. I've seen projects where voters in safe states
             | swap with voters in a swing state [0]. (Obviously these are
             | unverified, so they still contain a prisoner's dilemma.)
             | 
             | [0] https://en.wikipedia.org/wiki/Vote_pairing#United_State
             | s_pre...
        
         | csense wrote:
         | I came here to say this. The voting scheme described isn't
         | Pareto efficient; it's possible for pairs of participants to
         | make positive-sum private deals.
         | 
         | In the base scenario, Alice votes for A with 4 credits and Bob
         | votes for B with 4 credits. A, B each gets 2 votes.
         | 
         | In the private deal scenario, Alice/Bob agree to each vote for
         | A, B with 2 credits each. Then A, B each gets 2.818 votes.
        
         | Ar-Curunir wrote:
         | It's a good point; this article goes into detail about this
         | issue in existing deployments, and potential solutions:
         | https://vitalik.ca/general/2021/04/02/round9.html
        
       | Nuzzerino wrote:
       | _Builds MVP-quality product_
       | 
       |  _Announces that the world isn 't ready for the idea as a whole_
        
         | dane-pgp wrote:
         | Do you think it's never possible to determine the future
         | success of a product by attempting to build an MVP?
         | 
         | You could maybe try to argue that the implementation hadn't
         | reached the minimum level yet, and therefore wasn't an MVP and
         | it was too early to draw conclusions, but it sounds like you're
         | just assuming that.
        
         | timdaub wrote:
         | Hey, despite your comment sounding mean, I want to meaningfully
         | respond:
         | 
         | Where do you set the personal boundry for evaluating an
         | experiment as a failure or success?
         | 
         | E.g. in the case of social networks and what consequences
         | Facebook brought us. When is the right time for Mark Zuckerberg
         | to announce conclusive failure or success for his actions?
         | 
         | Pessimists say he should have admitted it years ago.
         | 
         | He himself doesn't even accept the premise of the argument.
         | Rather he sees it as his personal calling or responsibility to
         | build (source: see Lex Friedman podcast).
         | 
         | Who's right here?
         | 
         | Anyways, it isn't my intention to negatively associate digital
         | or quadratic voting. Rather the post is an attempt at adding to
         | a currently inconclusive picture through critique.
        
           | onionisafruit wrote:
           | That was a weird criticism. In my mind this gives more
           | credibility to both your article and your endeavors in
           | quadratic voting. The article has more credibility because it
           | isn't from somebody who has a bias against quadratic voting,
           | and your quadratic voting efforts have more credibility
           | because people see you are willing to see and address flaws
           | in the system.
        
       | timdaub wrote:
       | Hi, OP here. I'm grateful for getting this exposure. Thank you!
       | 
       | I wanna give a shout out to the commentators on /r/programming
       | and that we had a meaningful discussion that may be relevant too:
       | https://www.reddit.com/r/programming/comments/tptbzb/the_use...
       | <3
        
       | twic wrote:
       | On the point of the results being hard to interpret, and sanity-
       | check, i have a couple of thoughts.
       | 
       | Firstly, rather than just publishing the total number of votes,
       | and vote credits, for each choice, publish the histogram of vote
       | credits. 60 people allocated 1 credit, 40 people allocated 2
       | credits, 35 people allocated 3 credits, etc. That is sufficient
       | to verify the total votes for that choice, and across all
       | choices, to verify the total vote credits used, allowing sanity-
       | checking. It can also be used to give some sort of visual
       | indication of the structure of voting: imagine a bar comprising a
       | fixed-width slice per vote, sorted in order of ascending credits
       | per vote, coloured according to credits per vote. An option with
       | uniform support will have a uniform colour, with the intensity of
       | colour indicating the concentration of support; an option with
       | some weak and some strong supporters will have a gradient of
       | colour.
       | 
       | Secondly, rather than mapping credits to votes and just
       | displaying votes, consider n^2 - n of the credits allocated by a
       | voter to a choice 'wasted', and display a total of wasted credits
       | as an additional part of the bar. The first part of the bar shows
       | votes, and so which option wins, but the total bar shows credits
       | allocated, and so some measure of total support.
        
       | praestigiare wrote:
       | This is fairly interesting, but I do have to note that counting
       | the desire to not have pollution as the externality is...
       | interesting.
        
       | onionisafruit wrote:
       | I generally agree with the premise of the article and don't think
       | quadratic voting is a good option for a democratic government --
       | though it might make sense in other situations.
       | 
       | However I don't understand the point about not being able to use
       | all credits because you have to spend them buying whole numbers
       | of votes. Why not allow fractional votes? I realize there is
       | probably a good reason, but I don't see it immediately.
        
         | timdaub wrote:
         | You're right. After publishing, someone on Reddit told me that
         | fractional votes are technically OK.
         | 
         | If you look closely for it, I mention it in a footnote that I
         | added after publishing.
        
           | iainmerrick wrote:
           | If you're willing to edit the post, I suggest just removing
           | that whole section, or at least boiling it down to a couple
           | of sentences (here's a thing that went wrong, here's the
           | fix). It seems like a rather shallow observation that just
           | detracts from the deeper ones that follow.
        
             | timdaub wrote:
             | I had considered doing that.
             | 
             | But I think it'd paint a false picture. In the half a year
             | of developing the app, and me being mostly concerned with
             | correctly implementing the voting algorithm and
             | understanding the math - when reading Wikipedia and what is
             | outlined in Weyl's book, it wasn't obvious that fractal
             | votes can be used.
             | 
             | As a single tech freelancer working for a federally-funded
             | exhibition hall, I wanted things to be correct. So I stuck
             | to the script (aka the most credible sources accessible).
             | 
             | I've added the footnote in the article linking to a Reddit
             | post where someone claims having talked to Weyl about
             | fractal votes and that he positively reaffirmed it [1].
             | Anyone could comment that though.
             | 
             | But from a mathematical point of view, it isn't trivial (at
             | least for me) whether fractal votes represent the same
             | system as is currently laid as "quadratic voting".
             | 
             | Sure, if I end up completely understanding why fractal
             | votes are mathematically equal to natural-numbered votes,
             | I'll do as you suggested.
             | 
             | references:
             | 
             | - 1: https://www.reddit.com/r/radicalxchange/comments/tprsg
             | i/the_...
        
       | ajot wrote:
       | What I would change in the Strikedao voting app (for what I can
       | see from the videos): show people how much will next vote cost
       | them. So, if you haven't voted for option A, your first vote
       | costs 1. After voting for the first time, option A's cost grows
       | to 3 to cast your second vote, then to 5 to cast your third vote,
       | and so on. Showing an ascending odd-numbered cost for voting
       | would be more intuitive than thinking about square roots and
       | whatnot.
        
       | bentcorner wrote:
       | On the face of it it seems weird that votes for one thing can be
       | influenced by the existence of unrelated issues on the same
       | ballot.
       | 
       | It makes more sense if you're making a selection among many
       | people for one position, but if you have, say, 5 different issues
       | on a ballot, you can influence the impact of those 5 by adding
       | useless issues to the ballot. (e.g., if you are a pink legislator
       | you can feign partisanship and add a bunch of low-importance
       | purple issues to the ballot so that purple voters cannot easily
       | oppose your pink issue).
        
       | aimor wrote:
       | What a bizarre voting system, it values diversity of vote credits
       | which incentives people to organize their voting strategies.
       | Multiple people with overlapping concerns want to coordinate
       | their credit spending. People with extra credits and no desirable
       | issue to spend them on want to trade with others in similar
       | situations. Seems like a great way to bias voting against smaller
       | disorganized causes, unfairly suppressing minority representation
       | in the vote counts.
        
         | nopenopenopeno wrote:
         | Well put. This is the most important point. The ruling class is
         | normally (and especially these days) far more organized than
         | the working class. This is a voting system that will
         | aggressively suppress the influence of working class voters.
        
       | iainmerrick wrote:
       | I've followed a few links that explain the mechanism of quadratic
       | voting, but still haven't seen a simple explanation of why it
       | might be a good idea.
       | 
       | What makes quadratic voting better than just converting credits
       | directly into votes -- one credit, one vote? ("Cumulative
       | voting")
        
         | jerf wrote:
         | In this particular context it seems to just be one of a zoo of
         | competing alternatives with nothing in particular to recommend
         | it, and some serious drawbacks.
         | 
         | I've seen in proposed for voting in the real world where you
         | buy the credits with real money in some growing cost-per-
         | credit, as an attempt to control for rich people being able to
         | buy so much more voting power right now through lobbiests. It
         | has a certain cryptonanarchist or radical libertarian appeal,
         | but the engineer in me points out there doesn't appear to be a
         | path from here to there, since among other things you have to
         | figure out how to fully ban any other form of lobbying by the
         | rich, which is simply not practical. Not even if I include
         | "have a violent" revolution as an option, because no plausible
         | violent revolution would adopt this system at the end of it
         | either. I dunno if it's fair to say people are really hardcoded
         | to "one person, one vote", but for whatever reason it is
         | something that you can get people to generally agree as fair,
         | possibly just because everyone can easily see that the instant
         | you _visibly_ deviate from that there 's no longer in point in
         | voting because you will never get to the voting phase; the
         | voting body will never again do anything but argue about how to
         | vote.
         | 
         | While I think it's still hopelessly impossible, at least in
         | this context there's some meat to discuss to the proposal,
         | rather than just Yet Another Exotic Voting Method for small
         | groups.
         | 
         | (I have to add _visibly_ there because as previous sentences
         | show in that paragraph, I 'm well aware we don't have a "one
         | person, one vote" system in practice. In theory it's a
         | Republic, after all, not a Democracy, and in practice, anyone
         | who buys lobbiests has _vastly_ more voting power than you do.
         | But it _looks_ like we do, so it 's stable enough for now. It
         | can even be the case that everyone pretty much realizes it, but
         | it's stable enough. But make it _visibly obvious_ that 's not
         | what's happening and the fireworks will fly.)
        
           | dane-pgp wrote:
           | > you have to figure out how to fully ban any other form of
           | lobbying by the rich
           | 
           | In fact, if a society could work out how to do that, they
           | should do that first, and then they might find that all these
           | "let rich people have more voting power" proposals would
           | coincidentally disappear.
           | 
           | > it's a Republic, after all, not a Democracy
           | 
           | Please don't perpetuate that awful meme. A country can be
           | both, and the US is only "not a democracy" under the most
           | idiosyncratic definition of "democracy".
           | 
           | https://mises.org/wire/stop-saying-were-republic-not-
           | democra...
           | 
           | https://www.bloomberg.com/opinion/articles/2019-04-11/is-
           | u-s...
           | 
           | https://thebaffler.com/latest/were-a-republic-not-a-
           | democrac...
        
         | 6gvONxR4sf7o wrote:
         | The idea as I've heard it is that with quadratic costs, you'll
         | end up with people voting in proportion to how much they care.
         | If you care 3x as much as I do, you'll spend 3x as many votes
         | on it.
        
           | iainmerrick wrote:
           | The idea seems to be that if you care 3x as much, you'll keep
           | buying votes until the marginal cost of each new vote is 3x
           | greater. The marginal cost is linear, the total cost is the
           | integral of that which is quadratic.
           | 
           | The fact that you have a finite budget, so you can't just
           | arbitrarily keep buying votes until some threshold is met,
           | seems like a big flaw in the argument.
        
             | 6gvONxR4sf7o wrote:
             | Yeah, the _goal_ is to have number of votes voted be
             | proportional to how much you care. I don 't know how
             | accurately that pans out when this is really used.
        
         | timdaub wrote:
         | The most-comprehensive argument that motivates its existence,
         | I've found in Glen Weyl and Eric Posner's book "Radical
         | Markets."
        
           | jdwyah wrote:
           | Lazy Q, but do you know if there is a reason that the votes
           | need to be whole numbers? If I allocate 7 credits to
           | something is there any reason not to just count that as 2.65
           | votes?
           | 
           | (And by "any reason" I guess I mean "any reason besides lack
           | of comfort with non-whole numbers").
           | 
           | From here it seems like the general principle of social cost
           | still applies / doesn't have anything to do with the step-
           | function nature of things.
        
             | timdaub wrote:
             | I'll attempt explaining in my own words with the risk of
             | exposing my lack of understanding. I'm currently in the
             | office, so I don't have the book with me. So this is from
             | the top of my head.
             | 
             | In Weyl and Posner's book "Radical Markets" they motivate
             | quadratic voting as outlined as a way of preference voting
             | where a voter's desire intensity is represented in the
             | vote.
             | 
             | Their argument is practically outlined in the pollution +
             | city example I make in the original blog post and where,
             | with the sloppy figure I have attached [1], they reason
             | geometrically that "Nils" should "pay" for reducing the
             | electricity plant's pollution. If you look closely at that
             | figure (which is nicer in the book), you can see that the
             | plane where the cost functions intersect is a triangle.
             | 
             | I can't fully reproduce the mathematical reasoning here,
             | but how I understood it is that dependent on Nils's choice,
             | the externality he imposes has quadratic cost given that
             | the triangle's change is affected quadratically. In an
             | isosceles triangle, where volume V is defined dependent on
             | two same length sides, I can see that work out. But I've
             | never worked through that.
             | 
             | More intuitively, an example, I'm just making up is if
             | you're annoyingly snorting during a visit to the cinema.
             | 
             | If you're the only person snorting and you think that's OK,
             | but nobody else can understand the dialogue - you're not
             | only wasting your money but everybody else's. It's
             | quadratic because of the opportunity cost of everybody
             | wasting 2 hours but having all paid for the film. So both
             | the cost of the cinema running the movie for two hours and
             | everybody paying but not understanding makes your snorting
             | square the cost. Does that make sense? Please correct me if
             | I'm wrong.
             | 
             | So essentially, if Nils is picky with anti-pollution, his
             | pickiness costs the town's society quadratically - which is
             | why he should pay the quadratic cost of his pickiness
             | during governance.
             | 
             | references:
             | 
             | - 1: https://timdaub.github.io/assets/images/cost-of-
             | externality....
        
               | twic wrote:
               | The comment you're replying to asks one question - why do
               | votes need to be whole numbers? It doesn't seem to me
               | that this addresses that question at all.
        
           | iainmerrick wrote:
           | Is there a good summary anywhere besides just reading the
           | book?
           | 
           | I'm curious but skeptical. I would have thought that if there
           | is a good and straightforward justification, it would be in
           | the wikipedia page, but it's not. It simply says:
           | 
           |  _Quadratic voting is a variant of cumulative voting in the
           | class of cardinal voting. It differs from cumulative voting
           | by altering "the cost" and "the vote" relation from linear to
           | quadratic._
           | 
           | Apart from that there's no comparison to cumulative voting,
           | which seems a lot simpler and more robust against concerns
           | like collusion and sybil attacks. The only other mention of
           | "linear" is in a rather opaque paragraph marked "citation
           | needed".
           | 
           | If it's purely a way to allow people to buy votes without
           | having rich people completely corner the market, I guess it
           | makes some sense, but it still seems rather wrongheaded. If
           | you're going to give everybody the same number of virtual
           | tokens, there are no rich people to begin with. If you insist
           | on using an actual currency, there are other possible
           | mechanisms like a universal basic income.
           | 
           |  _Edit to add:_ Aha, I 've found a (the?) paper:
           | https://papers.ssrn.com/sol3/papers.cfm?abstract_id=2343956
           | 
           |  _Rational agents maximize their utility by setting marginal
           | cost equal to marginal benefit. This means that if John
           | values being able to incrementally move the outcome in his
           | favor twice as much as Sue values being able to incrementally
           | move the outcome in her favor, John will pay twice as much at
           | the margin as Sue does. For example, John buys 16 votes while
           | Sue buys 8 votes. The exact number of votes that John and Sue
           | buy depends on their estimates of how likely they will be
           | pivotal voters, as explained below, so if John buys 16 votes
           | for $256 (162 ), this does not mean that he values the
           | project at $256. But it does mean that he values the project
           | twice as much as Sue, who buys 8 votes._
           | 
           | This emphasis on marginal cost seems to ignore the fact that
           | John and Sue will be working with finite budgets -- the
           | overall real cost of the vote is important too! Unless I
           | misunderstand, the implication is that if the cost were
           | linear, John would buy an unbounded number of votes (as the
           | marginal cost never goes up) which seems absurd.
           | 
           | Particularly in the cases where quadratic voting is actually
           | being used in government, when e.g. lawmakers are given 100
           | tokens to split among different possibilities, I don't think
           | any of the above analysis applies at all, and it's not clear
           | that quadratic voting has any advantages over cumulative
           | voting.
        
             | afiori wrote:
             | I will be specifically talking about this demo
             | 
             | https://www.economist.com/interactive/2021/12/18/quadratic-
             | v...
             | 
             | I don't think that quadratic voting is relevant for the
             | case of "Many people need to answer a few shared questions"
             | as it happens it elections. I believe it is for the case
             | "one person needs to answer many questions" as it happens
             | in polling.
             | 
             | Of course it can be used in elections as a sort of
             | preference voting, but its effect is to punish extreme
             | opinions (you might be extremely opposed to Statement A but
             | might also want to keep some credits to express your milder
             | opinion about B, C, and D.
             | 
             | (of course this also opens more venues for manipulating
             | polling by adding duplicated similar questions...)
        
               | iainmerrick wrote:
               | That UI is excellent, but it doesn't explain _why_ it
               | should be quadratic and not linear. At first glance, it
               | seems actively bad, as I 'm penalised for focusing on
               | just a few issues!
               | 
               | Unfortunately the linked article is paywalled.
               | 
               | The motivating example in the QV papers I've just skimmed
               | is more about people voting on a sequence of yes-or-no
               | questions, buying some number of votes and being
               | compensated afterwards each time. That's totally
               | different from this one-shot, multiple-questions, fixed-
               | budget example.
        
             | timdaub wrote:
             | There's also all the academic literature of Weyl et al.
             | that makes the basis of the book, but I've found that to be
             | less accessible [1].
             | 
             | references:
             | 
             | - 1:
             | https://www.aeaweb.org/articles?id=10.1257/pandp.20181002
        
       | dane-pgp wrote:
       | I wonder if there's been much research into modelling voting as
       | an adversarial process in which different parties (and not
       | necessarily the political parties) try to attack the various
       | aspects of the process, including the stages before, during, and
       | after the vote-casting and counting takes place.
       | 
       | For example, we've seen attacks on voter registration and
       | availability of polling stations, and bizarre (but insidious)
       | schemes like deceptively-named candidates and misinformation
       | about when an election is held. We also have the problem of
       | "fraudits" where various groups try to undermine the confidence
       | in elections that have already taken place.
       | 
       | It seems like any attempt at electoral reform should take into
       | account this adversarial context, and consider any proposed
       | clever mathematical formula or any technology more complex than a
       | pencil to be part of the epistemological attack surface that
       | needs to be minimised as much as possible.
       | 
       | That doesn't mean that current systems are perfect, or that FUD
       | is an unbeatable strategy for opposing reforms, but it does mean
       | that it's not enough for a proposal to offer elections that are
       | more convenient or that have better psephological properties.
        
       | dwighttk wrote:
       | Yes. Every scheme I've seen to "improve" first past the post
       | brings in all sorts of problems that the big brain political
       | pundits are blind to (willfully or not).
        
         | dane-pgp wrote:
         | Do you really think that countries which use FPTP for elections
         | have a better political culture and public satisfaction than
         | countries which use more proportional systems?
         | 
         | It's not like electoral reform is some wild untested idea that
         | we don't have any data about, globally.
        
       | malfist wrote:
       | Quadratic voting seems like a very convoluted way to say: "The
       | rich should have all the votes"
       | 
       | If voting incurs a cost, and the more of that cost you can pay,
       | the greater your vote, then all that does is disenfranchise
       | people who cannot afford to vote.
       | 
       | This is just poll taxes 2.0, now with extra feudalism.
        
         | gs17 wrote:
         | Quadratic voting does not require the credits to be purchasable
         | with real money. Many implementations simply give every voter a
         | fixed number of credits to spend with no way to gain more.
        
           | malfist wrote:
           | That's interesting, I did not get that from the article. It
           | talked about voters who wanted less air pollution had to pay
           | the economic costs of voters that didn't care about air
           | pollution, but wanted lower electricity bills.
        
       | mdavis6890 wrote:
       | There is a chapter in the excellent book "Why Flip a Coin"
       | dedicated to exploring voting alternatives. The main point of the
       | chapter is that given three intuitively obvious requirements
       | (like adding a 3rd candidate should not change the relative order
       | of the first two) - it can be mathematically proven that NO
       | voting scheme will satisfy them.
       | 
       | See
       | https://en.wikipedia.org/wiki/Arrow%27s_impossibility_theore...
        
         | dane-pgp wrote:
         | > adding a 3rd candidate should not change the relative order
         | of the first two
         | 
         | This is, I think, the least justified requirement, since humans
         | do naturally reframe situations when extra information is
         | given, which can cause them to change their mind about previous
         | decisions.
         | 
         | To give a trivial example, suppose you were in a district which
         | historically had a Democrat and a Republican candidate, and you
         | always voted Democrat, but one year a far left independent
         | candidate became popular and you feared they would attract most
         | Democrat voters over to their camp. Given that scenario, it
         | might make sense for you to vote for a moderate Republican
         | instead.
         | 
         | In any case, I think that the significance of Arrow's
         | impossibility theorem is generally over-estimated (and it
         | spreads as a meme because people like to think that all voting
         | systems are bad so there's no reason to change the terrible one
         | they have).
         | 
         | For example, the theorem only applies to ordinal (ranked)
         | voting systems, not cardinal (rated) ones, and only proves that
         | the system cannot output "a community-wide (complete and
         | transitive) ranking", so it is still possible to elect a small
         | set of politicians who collectively embody the same preferences
         | as the voters, and in direct proportion to them.
        
           | twic wrote:
           | But all along, this person's preference is Democrat >
           | Republican > Independent. That doesn't change. The fact that
           | their best interests are served by casting a ballot which
           | doesn't reflect that is exactly the problem!
        
             | couchand wrote:
             | > their best interests are served by casting a ballot which
             | doesn't reflect that is exactly the problem!
             | 
             | You may be interested to hear about the Gibbard-
             | Satterthwaite theorem then. Any non-dictatorial system with
             | more than two alternatives is subject to tactical voting.
             | Whoops!
        
           | wtallis wrote:
           | You've described an example where the addition of a third
           | candidate causes a voter to strategically change who they're
           | going to vote for, based on the expected outcomes under a
           | particular voting system. That's not the same thing as the
           | voter's actual preferences changing, it's just a
           | manifestation of a limitation of a particular voting system.
        
             | couchand wrote:
             | What exactly do you mean by "the voter's actual
             | preferences"?
        
         | NathanielLovin wrote:
         | Arrow's impossibility theorem only applies to ordinal voting
         | systems. Quadratic voting is a cardinal system. Cardinal voting
         | still isn't perfect, but it does get around some of the
         | problems with ordinal systems.
        
           | notahacker wrote:
           | This form of cardinal voting has a particularly egregious
           | equivalent of the "additional candidate affects preference
           | ordering" issue in ordinal voting systems though. Unlike the
           | weird edge cases with preference ordering in ordinal votes,
           | the effects of adding additional votes on reducing certain
           | voting blocs' influence on other issues where ppeoplemust
           | divide a budget across multiple issues often lead to
           | intuitive (trivially simple, even) strategies to manipulate a
           | particular outcome.
           | 
           | If you can add a proposition to the ballot paper which
           | sufficiently threatens a particular group, they're forced to
           | waste votes defending themselves against it, which means they
           | have less influence on other issues they might also care
           | about. As far as I can see the quadratic nature makes it
           | worse, by making it more plausible a minority could actually
           | lose a vote that threatens them if they only spent _most_ of
           | their credits defending themselves against it.
           | 
           | That's a bigger UX issue than non-sophisticated voters not
           | really grasping the budgeting detail.
        
           | contravariant wrote:
           | I'm not sure quadratic voting is the best cardinal voting
           | system though. In particular it still fails to satisfy
           | independence of irrelevant alternatives. So sure Arrow's
           | impossibility may not apply, but the conclusion isn't
           | actually different.
        
       | baoyu wrote:
       | Here's a quadratic voting demo that looks nice and provides more
       | intuition:
       | https://www.economist.com/interactive/2021/12/18/quadratic-v...
        
         | karaterobot wrote:
         | This is great!
         | 
         | And it reveals another (probably unsolvable?) UX problem with
         | quadratic voting: it takes so much longer to allocate votes by
         | comparison to a thumbs-up / thumbs-down vote.
         | 
         | For myself, I did a pass through the issues, supporting or
         | opposing each issue with a single vote. Then, I did another
         | pass to add additional votes to each issue in proportion to how
         | much I cared, while carefully paying attention to how many
         | issues were left to be voted on, and my remaining "budget" of
         | votes. Then, I did a final series of passes to rebalance
         | everything, trying to make it as reflective of my positions as
         | possible, while using as many votes as I could (so as not to
         | leave any crumbs of democracy on the table, so to speak).
         | 
         | The whole thing was actually really complex, and not done in
         | "linear time" like a traditional ballot. And it wasn't because
         | I thought more about the issues, but purely because the rules
         | of the system introduced so much more overhead.
         | 
         | Not saying I dislike the idea of quadratic voting, just that
         | you can really feel the difference.
        
         | timdaub wrote:
         | thanks for sharing, I love the UI!
        
           | jdwyah wrote:
           | That UI really is good.
           | 
           | The large number of votes (100) and issues (10) seems to
           | reduce the issue around not being able to "spend" all your
           | votes as well. When I've only got 25 it feels particularly
           | wasteful to not be able to spend 7. But with 100 and 10
           | choices I really had a lot more degrees of freedom.
           | 
           | I run a small ranking app and have previously landed on
           | Schulze method for calculating the rankings.
           | http://blog.forcerank.it/counting-votes-is-hard I'm going to
           | have to think about adding quadratic as an option though.
        
             | dllthomas wrote:
             | For the example given, it seems like the majority criterion
             | is actually not desirable.
             | 
             | Picking a talk topic that everyone will like a lot _is a
             | better outcome_ than picking another slightly preferred by
             | most but completely uninteresting to the rest.
        
         | amelius wrote:
         | Why do the questions never include my purchasing power, given
         | my current financial situation?
         | 
         | This is what 50% of the population cares about, yet their votes
         | are stolen away by focusing on things like immigration and
         | terrorism.
         | 
         | The mismatch in these questions is why lower social classes
         | often vote for populist right wing parties, instead of in their
         | own best interest.
        
       | ComputerGuru wrote:
       | This is susceptible to ballot poisoning: lobby to put something
       | you had no intention of doing but your opposition feels very
       | strongly about on the ballot and then watch them waste their
       | credits "reaffirming" the status quo of the hot-button issue
       | while educating "your" voters to prioritize the actual issue
       | under contention.
       | 
       | Imagine a ballot with one contentious question A. Opposition Y
       | adds a question B they know will flop but is guaranteed to
       | disproportionately attract all the attention _of the other party_
       | to the ballot. Party X voters waste their credits on the red
       | herring question B (which has greater than 50% support in the
       | overall population anyway and would never fail them) while
       | opposition Y advises its voters to spend the credits on the
       | actual question A they care about.
       | 
       | As a completely contrived example, the real question is a
       | controversial "add a carbon tax" that could go either way and one
       | party either adds "ban all abortions in all cases for everyone"
       | or "ban all firearms for all people" to the ballot to misdirect.
       | Either of these is guaranteed to disproportionately attract all
       | the attention of one of the parties more than the other despite
       | neither having a remote chance of passing. Because of the
       | phrasing and the topic chosen, even if you don't educate your
       | voters you can rely on the fact that _their_ voters simply care a
       | lot more about the topic than yours do.
        
         | shonenknifefan1 wrote:
         | I had assumed when reading this that the voting credit budget
         | would be allocated per question rather than across the entire
         | ballot. However I don't think the article gave an example of a
         | ballot with multiple questions.
         | 
         | I'd be interested to learn which way this being implemented in
         | practice for multi-question ballots.
        
           | thechao wrote:
           | I was confused by GP's post, as well! I have only seen
           | quadratic voting used to decide amongst non-binary questions:
           | positions with at least 3 (or more) possible outcomes. It
           | seems weird to mix voting across a bunch of different issues.
        
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       (page generated 2022-03-29 23:01 UTC)