Comment by AnthonyMouse

Comment by AnthonyMouse 7 months ago

15 replies

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> Whereas with ranked voting, the person who gets the most #1’s might not win and that can confuse some citizens.

Not ranked voting, ranked voting is still very broken. Rated voting. Approval voting is a rated voting system.

Score voting: Rate each candidate on a scale of 1 to 10.

Approval voting: Rate each candidate on a scale of 0 or 1.

Score voting (or STAR) is generally better and the argument that people are going to be confused by "that thing they use at the Olympics" is nonsense, but approval voting is fine if you want to silence the complainers while still using something that basically works.

amalcon 7 months ago

Score voting is just approval voting with an additional permitted tactical error.

In both systems, the correct tactic is to determine the two candidates most likely to win. Then, assign maximum score to whichever of those is better and to everyone preferable to that candidate.

It is never correct to assign a score between the minimum and the maximum, so why allow it in the first place?

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  • AnthonyMouse 7 months ago

    > It is never correct to assign a score between the minimum and the maximum, so why allow it in the first place?

    Because it is often correct.

    Suppose there are candidates A, B and C. Candidates A and B are each polling around 6/10 and candidate C is polling around 4/10, but candidates A and B are quite similar to each other and share a base of support. According to your strategy, A and B are the two most likely to win, so if you prefer A then even though you still prefer B to C you refuse to express your preference and instead assign 10/10 to A and 1/10 to B and C. The voters who prefer candidate B do the same. The result is that A and B end each up at 3.5/10, C ends up at 4/10 and C wins. In other words, you've devolved back into first past the post and caused your least favored candidate to win because of your erroneous strategizing.

    By contrast, if you assign 10/10 to A, 5/10 to B and 1/10 to C, you've given A a significant advantage over B without assigning B such a low score that you could deliver the election to C if C defeats A.

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    • amalcon 7 months ago

      In your scenario, I have made a mistake in assessing which two candidates are most likely to win -- because I took vote shares as win probabilities. This is also a mistake, and it is a mistake no matter the voting system or the next step in your strategy.

      You're also assuming that everyone axiomatically uses the same strategy as me. If A-voters use your strategy and B-voters use my strategy, then B is straightforwardly favored to win. This results in a prisoner's dilemma, with its well-known Nash equilibrium in favor of defection.

      > you've devolved back into first past the post

      Correct. The potential for this to happen is one of the drawbacks of rated voting systems. It's also, through a different mechanism, one of the drawbacks of ranked systems. It doesn't mean we shouldn't try, since both alternatives give some ability to hedge against incorrect assessments.

      > By contrast, if you assign 10/10 to A, 5/10 to B and 1/10 to C, you've given A a significant advantage over B without assigning B such a low score that you could deliver the election to C if C defeats A.

      I can accomplish the same mathematical thing by assigning 10/10 to A, 1/10 to C, and flipping a coin to determine whether to give B 1/10 or 10/10. Both give the same odds of winning to A and B (well, mine gives B slightly higher odds because its average is 5.5 -- but you get the point). The only difference is that your method outsources the randomness to the rest of the electorate, rather than generating it yourself.

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      • AnthonyMouse 7 months ago

        > In your scenario, I have made a mistake in assessing which two candidates are most likely to win -- because I took vote shares as win probabilities.

        Your problem is that your voting strategy changes which two candidates are most likely to win. If everyone votes their actual preferences then it's A and B. If too many people vote according to your strategy, C becomes a frontrunner.

        > You're also assuming that everyone axiomatically uses the same strategy as me.

        I'm only assuming that some proportion of voters use the same strategy as you. The higher that proportion is, the more likely it is that C wins instead of A or B. It doesn't have to be 100% of people to cross the threshold into changing the outcome.

        > If A-voters use your strategy and B-voters use my strategy, then B is straightforwardly favored to win. This results in a prisoner's dilemma, with its well-known Nash equilibrium in favor of defection.

        That isn't a prisoner's dilemma. A's voters prefer that B win over C and B's voters prefer that A win over C, so they each have the selfish incentive to give their second choice a higher score than their third choice to prevent the worst-case outcome.

        > I can accomplish the same mathematical thing by assigning 10/10 to A, 1/10 to C, and flipping a coin to determine whether to give B 1/10 or 10/10.

        But then the voting system is receiving less information from you. Requiring your preferences to be expressed statistically increases the error bars for no reason. Also, most people are not going to do that and requiring them to in order to express their preferences is needlessly confusing.

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  • ClayShentrup 7 months ago

    tactical error is GOOD, because it donates more utility to society than that non-strategic voter loses. AND for a lot of not-so-math-savvy voters, an honest score ballot is actually a better vote than a botched attempt to use strategic approval thresholds.

    http://scorevoting.net/RVstrat6

    https://www.rangevoting.org/ShExpRes

    > It is never correct to assign a score between the minimum and the maximum, so why allow it in the first place?

    it would help you to spend at least 30 seconds researching a complex field like voting methods before asking a deeply misguided question like this.

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