Should this be broken up into sub-posts?
Jameson Quinn
Karma: 1,183
A voting theory primer for rationalists
1) In most cases, the voting method options when voting on competing (non-sapient) plans are the same as those for candidates. In fact, as I said, Arrow’s theorem and Sen’s theorem were originally posed as being about voting over world-states rather than candidates. And approval voting, with a 50% threshold, has been used various times in practice for voting on incompatible ballot initiatives.
The exception to this rule is when voting methods use delegation in some way (such as “liquid democracy”, SODA, PLACE, and to a much lesser extent 3-2-1). Obviously, these methods require sapient candidates, or at least some kind of impartial divergence measure over candidates.
2) As I hinted, I think that the academic literature on this tends to focus more on the axiomatic/Arrovian paradigm than it should. I suspect that there is some political science research that relates, but aside from a few simple results on spoiled ballots under IRV (they go up) I’m not familiar with it.
3) Organizations are probably more able to tolerate “complicated” voting methods — especially organizations of “nerds”, such as Debian or the Hugo awards. But my intuition in this area is based on anecdotes, not solid research.
4) Hmm… I’ll have to think about that one, I’ll get back to you.
Actually, I was talking about the kind of methods discussed here.
As to Schulze and Ranked Pairs, these two are very similar in philosophy. In terms of criteria compliances and VSE, RP is slightly superior; but Schulze has the advantage of Markus Schulze’s energetic promotion.
Note that I don’t endorse that page I linked to, it’s just the best source I could find for definitions of “improved Condorcet” methods.
“U/A” is some strange class of voting scenarios where voters have a clear a priori idea about what is “unacceptable” versus “acceptable” and strategize accordingly. I don’t think it’s analytically very helpful.
I’ve written a primer on voting theory that’s relevant to the voting method issues discussed here.
I haven’t mentioned futarchy (“markets for predictions, votes for values”) at all here. Futarchy, of course, would not be classed as a voting method in my typology; it’s something bigger than even than my concept of a voting system. I think that the main useful thing I can say about futarch is: if you’re going to spend energy on it, you should spend some energy on understanding lower-level voting methods too.
ETA: I guess I think I can expand on that a bit. The issue is that when you embed one system inside another one, there’s some inevitable bleed-over in terms of incentives. For this meta-reason, as well as for the simple reason of direct applicability, one lesson from voting theory that I think would apply to futarchy is that “patching a problem can make it worse, because strategic outcomes can be the ‘opposite’ of unstrategic ones.” That’s an intuition that for me was hard-won, and I wouldn’t expect it to be easy for you to learn it just by hearing it. If that’s true and you still want to learn it, spend some time thinking about honest and strategic outcomes in various voting methods in the five levels of pathology I mentioned above. The playable exploration I mention at the end will substantially focus on these ideas, in a way I hope will be visually and interactively easy to digest.
I’ve been moderately hard on IRV, and its supporters, in the above. I want to state here for the record that though IRV is my least-favorite serious* reform proposal, I think that it would solve a substantial fraction of the voting-system dysfunction of FPTP; that if IRV were more of a focus of this essay than it is, there are other decent pro-IRV arguments I could include; and that there are IRV supporters whose intellect and judgement I respect even as I disagree with them on this.
*That excludes Borda. #SorryNotSaari
The voting example is good — contingent on the voting system being plurality/FPTP, as used in most of the English-speaking world. In better voting methods, no coordination, thus no common knowledge, would be needed.
5 general voting pathologies: lesser names of Moloch
This is a theory post. I post activism stuff elsewhere.
(Anybody reading this in Somerville, MA who’s interested in activism on this, get in touch with me via gmail. Obvious address, both names. Also goes for other parts of US, or for BC, less urgently.)
I did talk about Arrow’s Theorem in my first post (again, can’t link right now, but it’s the “Voting Theory Primer for Rationalists”).
Also, I acknowledge in the last two pathologies here that they can’t all be solved. That is: if you actively punish CD defection so as to make cooperation a strong equilibrium, you allow center squeeze and so create pernicious 2-party equilibria. And no strong equilibrium can exist in case of a Condorcet cycle; that’s essentially the basis of Arrow’s theorem and thus also Gibbard and Satterthwaite’s.
But Arrow’s theorem only applies to ranked (ordinal) methods. Which is why I focus more on G-S. And you yourself acknowledge that when you mention cardinal voting.
The defects of cardinal voting are obvious: it becomes a pointless game of who can say the biggest number. If you limit the range of numbers allowed, it becomes score voting; which strategically reduces to approval voting; which I do discuss above.
There has definitely been attention to this question. All of the proposals I support in practice (Approval, 3-2-1, or STAR for single-winner; and PLACE for multi-winner) are among the simpler to vote and to explain.
But most of the research is in the form of proprietary focus groups or polling, so unfortunately there’s no good source I can point you to. I’m working to change that.
Links added.
Thanks, fixed. I also added a paragraph at the end.
This is a system where voters can give +1, 0, or −1 points to candidates in two-member districts, and the highest-score candidates win. So far, that sounds like score voting. However, there are also limits on how many candidates a given voter can support (4) and oppose (2), making this method something like single non-transferable voting.
This voting method is not mathematically clean, and is subject to every one of the pathologies I described. It’s not particularly hard to describe, but also a bit confusing at first glance. It is probably less likely to be caught in lesser-evil than FPTP, but that’s the best thing I can say about it. Verdict: thumbs emphatically down.
The point of SODA isn’t so much as a serious proposal; I prefer 3-2-1 for that, mostly because it’s easier to explain. SODA’s advantage is that, under “reasonable” domain restrictions, it is completely strategy-free. (Using my admittedly-idiosyncratic definition of “reasonable”, it’s actually the only system I know of that is. It’s a non-trivial proof, so I don’t expect that there are other proposals that I’m unaware of that do this.) Forcing candidates to pre-commit to a preference order is a key part of proving that property.
I do see the point of your proposal of having post-election negotiations — it gives real proportional power to even losing blocs of voters, and unifies that power in a way that helps favor cooperative equilibria. Some of that same kind of thinking is incorporated into PLACE voting, though in that method the negotiations still happen pre-election. Even if post-election negotiations are a good idea, I’m skeptical that a majority of voters would want a system that “forced” them to trust somebody that much, so I think keeping it as a pre-election process helps make a proposal more viable.
I’m assuming that “we” is the USA; and “the system” is FPTP (that is, you’re ignoring the electoral college and the system of primaries and redistricting).
Approval is just as easy to understand, and in fact easier to avoid ballot spoilage.
3-2-1 and STAR are both a bit more complicated, but not much; either one can still be distilled down to 9 words.
PLACE is significantly more complicated for vote-counting, but to cast a ballot, it’s still just about as simple as FPTP. In fact, if you take into account the fact that you are more free to ignore strategic concerns, it’s arguably simpler.
Certainly, that’s a reasonable point of view to take. If you fully embrace utilitarianism, that’s a “solution” (at least in a normative sense) for what you call problem (1). In that case, your problem (2) is in fact separate and posterior.
I don’t fully embrace utilitarianism. In my view, if you reduce everything to a single dimension, even in theory, you lose all the structure which makes life interesting. I think any purely utilitarian ethics is subject to “utility monsters” of some kind. Even if you carefully build it to rule out the “Felix” monster and the “Soma” monster, Godel’s incompleteness applies, and so you can never exclude all possible monsters; and in utilitarianism, even one monster is enough to pull down the whole edifice. So I think that looking seriously at theorems like Arrow’s and Sen’s is useful from a philosophical, not just a practical, point of view.
Still, I believe that utilitarianism is useful as the best way we have to discuss ethics in practice, so I think VSE is still an important consideration. I just don’t think it’s the be-all or end-all of voting theory.
Even if you do think that ultimately VSE is all that matters, the strategy models it’s built on are very simple. Thinking about the 5 pathologies I’ve listed is the way towards a more-realistic strategy model, so it’s not at all superseded by existing VSE numbers. And if you look seriously at the issue of strategy, there is a tension between getting more information from voters (as you suggest in your discussion of (2), and as would be optimized by something like score voting or graduated majority judgment) and getting more-honest information (as methods like 3-2-1 or SODA lean more towards).
(I had several hundred karma on the old Less Wrong site under a nym. Is there both a reason to want to reclaim that and a way to do so?)