I think there are many of us here who prefer some voting system or another over approval voting. I also think there is room for improvement. However, approval voting has a huge advantage in its simplicity and potential for integration into existing infrastructure. This is totally besides the comparisons to make in terms of game theoretical stability with Condorcet methods and expressivity with Score or others.

My thought is that, if we are really going to make progress by consolidating our support behind a single voting system, then realistically, Approval voting fits the bill. That isn’t to say that it should be the final destination for voting reform, but it would absolutely be a major step forward. While IRV is something of a tokenism, Approval would be an actual game changer.

Any thoughts about this are welcome.

This is a minor attempt to modify Condorcet methods in a simple way to become more responsive to broader consensus and supermajority power. It’s sort of like the reverse of STAR and may already be a system that I don’t know the name of. In my opinion, the majority criterion is not necessarily a good thing in itself, since it enables tyrannical majorities to force highly divisive candidates to win elections, which is why I’ve been trying pretty actively to find some way to escape it.

For the moment I will assume that a Condorcet winner exists in every relevant case, and otherwise defer the replacement to another system.

First, find the Condorcet winner, which will be called the “primary” Condorcet winner. Next, find the “secondary” Condorcet winner, which is the Condorcet winner from the same ballots where the primary Condorcet winner is removed everywhere.

Define the Borda difference from B to A on a ballot as the signed difference in their ranks. For example, the Borda difference from B to A on the ballot A>B>C>D is +1, and on C>B>D>A is -2.

If A and B are the primary and secondary Condorcet winners, respectively, then we tally all of the Borda differences from B to A. If the difference is positive (or above some threshold), then A wins, and if it is negative or zero (or not above the threshold), then B wins.

For example, consider the following election:

A>B>C>D [30%]
A>B>D>C [21%]
C>B>D>A [40%]
D>B>C>A [9%]

In this case, A is a highly divisive majoritarian candidate and is the primary Condorcet winner. B is easily seen to be the secondary Condorcet winner. The net Borda difference from B to A is

(0.3+0.21)-2(0.4+0.09)<0

Therefore B would be chosen as the winner in this case.

Some notes about this method:
It certainly does not satisfy the Condorcet criterion, nor does it satisfy the majority criterion. These are both necessarily sacrificed in an attempt to prevent highly divisive candidates from winning the election. It does reduce to majority rule in the case of two candidates, and it does satisfy the Condorcet loser criterion, as well as monotonicity and is clearly polynomial time. It can also be modified to use some other metric in the runoff based on the ballot-wise Borda differences.

Continuing with the above example, suppose that the divisive majority attempts to bury B, which is the top competitor to A.
This will change the ballots to something like

A>C>D>B [30%]
A>D>C>B [21%]
C>B>D>A [40%]
D>B>C>A [9%]

And if the described mechanism is used in this case, we will find instead that C is elected. So burial has backfired if B is "honestly" preferred over C by the divisive majority, and they would have been better off indicating their honest preference and electing B.

And again, suppose that the divisive majority decides to bury the top two competitors to A, namely B and C, below D, keeping the order of honest preference between them. We will find

A>D>B>C [30%]
A>D>B>C [21%]
C>B>D>A [40%]
D>B>C>A [9%]

In this case, the secondary Condorcet winner is D, and the mechanism will in fact elect D, again a worse outcome for the tactical voters.

Finally, suppose that they swap the order of honest preference and vote as

A>D>C>B [30%]
A>D>C>B [21%]
C>B>D>A [40%]
D>B>C>A [9%]

Still this elects D.

As a general description, this method will elect the Condorcet winner unless they are too divisive, in which case it will elect the secondary Condorcet winner, which will necessarily be less divisive. I believe that choosing the runoff to be between the primary and secondary Condorcet winners should maintain much of the stability of Condorcet methods, while the Borda runoff punishes burial and simultaneously addresses highly divisive candidates.

This is a concept I had in mind which may already have been described, although not all of the logistics are necessarily hashed out and there may be issues with it. The idea is described below, but first I want to make a connection to “cake-cutting.” The standard cake-cutting problem is when two greedy agents are going to try to share a cake fairly without an external arbiter. An elegant solution is a simple procedure where one agent is allowed to cut the cake into two pieces, and the other agent is allowed to choose which piece to take for themselves. The first agent will have incentive to cut the cake as evenly as discernible, since the second agent will try to take whichever piece is larger. In the end, neither agent should have any misgivings about their piece of cake.

So this is my attempt to apply that kind of procedure to political parties and representatives. Forgive my lack of education regarding how political parties work:

• There should be a government body that registers political parties and demands the compliance of all political parties to its procedures in order for them to acquire seats for representation;
• (Eyebrow raising, but you might see why...) Every voter must register as a member of exactly one political party in order to cast a ballot (?);
• Each political party A is initially reserved a number of seats in proportion to the number of voters with membership in A; the fraction of seats reserved for A is P(A). however
• For each pair of political parties A and B (where possibly B=A), a fraction of seats totaling P(A~B):=P(A)P(B) will be reserved for candidates nominated by A, and elected by B; these seats will be called ambassador seats from A to B when B is different from A, and otherwise will be called the main platform seats for A;
• Let there be a support quota Q(A~B) for the number of votes needed to elect ambassadors from A to B, and call P(A~B) the ambassador quota of party A for B. If E(A~B) is the fraction of filled A-to-B ambassador seats (as a fraction of all seats), I.e. nominees from A who are actually elected by members of B, then A will only be allowed to elect P(A~A)*min{min{E(A~B)/P(A~B), E(B~A)/P(B~A)}: B not equal to A} of its own nominees. That is, the proportion of reserved main-platform seats that A will be allowed to fill is the least fraction of reserved ambassador seats it fills in relation to every other party, including both the ambassadors from A to other parties, and the ambassadors from other parties to A.

This procedure forces parties to also nominate candidates that compromise between different party platforms in order to obtain seats for any main-platform representatives. If a party fails to meet its quota for interparty compromises, it will lose representation. On the flip side, this set up will also establish high incentives for other parties to compromise with them in order to secure their own main-platform representation. In total, this system would give parties high incentives to compromise with each other and find candidates in the middle ground, which will serve as intermediaries between their main platforms.

Basically, here the outlines indicate seats open to be filled by candidates who are nominated by the corresponding party, and the fill color indicates seats open for election by the corresponding party:

Seats with outlines and fills of non-matching color are ambassador seats, and seats with matching outline and color are main platform seats. In terms of party A, by failing to nominate sufficiently-many candidates who would meet the support quota Q(A~B) to become elected as ambassadors from A to B, or by failing to elect enough ambassadors from B to A, party A restricts its own main platform representation and that of B simultaneously. By symmetry the reciprocal relationship holds from B to A. Therefore all parties are entangled in a dilemma: to secure main-platform representation, parties must nominate a proportional number of candidates who are acceptable enough to other parties to be elected as ambassadors.

To see that all needed seats are filled in the case of a stalemate, where parties refuse to nominate acceptable candidates to other parties and/or refuse to elect ambassadors, the election can be redone with the proportions being recalculated according to the party seats that were actually filled.

The support quotas collectively serve as a non-compensatory threshold to indicate sufficient levels of inter-party compromise. Ordinary PR is identical to PR with ambassador quotas but with all support quotas set to zero, whereby there is no incentive to nominate compromise candidates.

The purpose of this kind of procedure is twofold: firstly, it should significantly enhance the cognitive diversity of representatives, and secondly, it should significantly strengthen more moderate platforms (namely those of the ambassadors) that can serve as intermediaries for compromises between the main platforms of parties. Every party A has a natural “smooth route” from its main platform to the main platform of every other party: The main platform of A should naturally be in communication with ambassadors from A to B, who should naturally communicate with ambassadors from B to A, who should naturally communicate with the main platform of B.

Also, this procedure gives small parties significant bargaining power in securing representation. Large parties will have much more representation to lose than the small parties that are able to secure seats if the small parties refuse to elect any ambassadors, so rationally speaking, large parties should naturally concede to nominating sufficiently many potential ambassadors whose platforms are closer to the main platforms of those small parties. The same rationale holds for the potential ambassadors nominated by small parties, who also should tend to have platforms closer to the main platform of the small party.

Finally, this system creates significant incentives for voters to learn about the platforms of candidates from other parties who stand to reserve seats for representatives.

@rob especially if the state is a swing state, making it more difficult for the large parties to secure voters for their platform I think would be a significant influence forcing large parties and their candidates to more scrutinizingly determine the real interests of voters in those states. It may dilute the interests of less competitive states, but since the competitive states are crucial to obtaining the presidency, the large parties will still have to invest strongly in the interests of voters in those states in order to compete with alternatives (and obviously each other) for the crucial swing points. This may lead to something like an arms race of concessions, which happened in New Zealand in 1996 and led to the national adoption of a PR system, according to Arend Lijphart. Obviously that's quite a leap for the U.S., but maybe a less extreme analogue is not so far-fetched.

Maine is one of the thirteen most competitive states for elections according to a 2016 analysis (Wikipedia: Swing state), so I’m not sure their recent establishment is actually strategically foolish, although it’s possible that it wasn’t fully thought through. I agree it isn't clear.

I think it will definitely be interesting to observe how the current political apparatus responds to Maine--and apparently, more recently, and strangely, Alaska:

https://news.yahoo.com/alaska-is-about-to-try-something-completely-new-in-the-fall-election-193615285.html

Since Alaska is far from competitive, I do think this transition was in fact foolish for the reasoning you stated, but it remains to be seen. If we saw a state like Florida transition to a system like Maine's, it would be very interesting to study the relative differences between federal treatments of Florida, Maine, and Alaska as a case study for how "swingy-ness" might influence the effect of such voting system transitions. If Maine experiences an increase in federal power, it would be a good case for the remaining swing states to make a similar transition. If that occurred, the swing states would become a platform foothold for alternative parties to grow.

@k98kurz I don’t think there should be any uncertainty in the default for a voter’s ballot.

@lime the point of this post isn’t to argue that approval voting is superior to other methods or that modifications wouldn’t improve approval voting, it’s to point out that despite other methods being potentially superior, standard approval voting is probably the most realistic target for near future steps toward substantially reformed voting.

Unfortunately, more choices does mean the system is more complicated. You can observe that the addition of even a very simple, marginal modification as you suggest already raises questions. Every question about a method is an opportunity for distrust to be exploited, even if the method is ultimately better. Plurality is terrible, but almost nobody had questions about it, and that’s why it’s stuck around for so long. Do you see what I mean? I may be a bit jaded, but I’m hoping to be realistic.

I don’t mean to be a downer, but my point is a bit sad: in terms of what people would prefer, such as more choices or buttons, what we have to deal with is exactly the fact that people are having a hard time getting what they prefer. The political status quo is strongly opposed to voting reform, it will have to relinquish substantial power and accountability to the people under an effective voting system. There’s a reason only flawed tokenisms like IRV have passed through legislature in recent times. In fact, there is a history of voting reforms being enacted and then reversed.

I just learned about this now. It’s a Smith compliant method, and is participation compliant up until necessary randomization.

https://en.wikipedia.org/wiki/Maximal_lotteries

Basically, you form the majority margin matrix Mij over candidates. Then consider the two player game where each player chooses one candidate: if player 1 chooses i, and player 2 chooses j, then player 1 gets Mij and player 2 gets -Mij.

This game has at least one mixed strategy Nash equilibrium, which is a distribution over candidates. A maximal lottery selects a candidate at random according to one such mixed strategy Nash equilibrium. In this sense, a maximal lottery is a mixed “candidate” that cannot be challenged by a majority.

Occasionally maximal lotteries are non-unique, but they often are. A trivial case is when a Condorcet winner exists, in which case the maximal lottery selects the Condorcet winner as a pure strategy. Orthogonally, if there is an odd number of voters, and if preferences are strict, the maximal lottery is always unique. Otherwise, symmetries like multiple dominance components in the Smith set can induce degeneracies.

Still, any maximal lottery satisfies probabilistic notions of participation, where participation cannot reduce the chances of a preferred outcome for a voter.

I think this is nearly the “right” notion of compliance. There is only slight room in choosing which maximal lottery to implement. For example, in case of degeneracy, one could choose a maximal lottery that optimizes expected score. Or, maybe compute Jeffrey’s prior over maximal lotteries, and then sample a maximal lottery accordingly.

What thoughts do others have?

@toby-pereira yes you’re right, it was just a thought that occurred to me when I was thinking about how to discourage bullet approvals, but it has irreconcilable flaws that are now apparent.

@democrates I meant a Condorcet winner only among the front runners (for example, the candidates with the top K scores, here we are taking K=2). If there is no Condorcet winner among them, then we can choose the top scoring candidate.

In your case, if two candidates have the same second-greatest score, and the three front runners form a Condorcet cycle, then you can use the scores to break the tie. If this was used, then Jill Stein would have won the election.

That isn’t “the correct” solution (there is no such thing), but it is somewhat less arbitrary than flipping a coin or operating by alphabetical order, neither of which has anything to do with relevant information that is readily available on the ballots.

If we were being engineers about choosing a high quality candidate to win the election, we could even compute the distribution of scores, take the candidates whose scores exceed some elbow point, and find the Condorcet winner among those candidates with the top scoring candidate as the backup if no Condorcet winner exists. That’s basically a generalization of STAR with a dynamic front-runner selection method.

There are other ways to proceed. For example, we could remove Condorcet losers, then try to find the Condorcet winner of all remaining candidates, iteratively eliminating the lowest scoring candidate until a Condorcet winner emerges.

@k98kurz mirroring @Lime, I think any advantage conferred to one candidate over any other in an election should be granted on an opt in basis. A voter shouldn’t have to opt out from conferring an advantage to a candidate.

@poppeacock a Condorcet method is defined in terms of the notion of a “Condorcet winner”, which is a candidate that beats every other candidate in a majoritarian head-to-head match up, also called a “beats all” winner. There can be at most one Condorcet winner in an election; however, there are pathological cases when a Condorcet winner does not exist at all, caused by what are known as Condorcet cycles.

The classic example is three voters using rank ballots over three candidates:

V1: A>B>C
V2: B>C>A
V3: C>A>B

You can see that A>B 2:1, B>C 2:1, but C>A 2:1. So A>B>C>A is a Condorcet cycle, which is a generalized “rock-paper-scissors” situation. Whichever candidate you choose as the winner, there is some majority of the voters who would have preferred a different candidate. That’s the unfortunate thing that happens when a Condorcet winner doesn’t exist…

Regardless, a Condorcet method is any method that guarantees electing the Condorcet winner when one exists. Condorcet methods differ in how they reconcile choosing a winner when the Condorcet winner does not exist, I.e. in effect how they determine which majority group(s) to jilt.

So for example, if Ranked Robin doesn’t specify how it resolves when there is no Condorcet winner, then it’s really a blanket term for Condorcet methods in general. Or maybe it’s a label for a particular curated subset of Condorcet methods.

There are many Condorcet methods, including Ranked Pairs, Schulze’s method, Copeland’s method, Minimax, and Bottom-Two-Runoff (by Tideman).

I like Bottom-Two-Runoff because it’s efficient and also equivalent to a seemingly (but not actually) more robust system: https://www.votingtheory.org/forum/topic/564/bottom-n-and-bottom-2-runoffs-are-equivalent

@poppeacock I see, so the site is using “Ranked Robin” as the umbrella term for any Condorcet method?

@jack-waugh I agree, PR is probably preferable in many ways to alternatives. Still, I think we’re too entrenched in the way our current system works and it may be most effective to start by modifying single-winner systems, specifically transitioning from choose-one plurality to approval plurality.

@poppeacock yes it seems to be a rebranding of Ranked Robin; from your link:

“Carmen won the most match-ups against other candidates, so she is elected the winner.”

I do notice often that these pro- rank-based voting sites almost never address the issues with reconciling the possible nonexistence of a Condorcet winner.

Is the main advantage of Ranked Robin over other Condorcet methods that it is precinct summable?

@jack-waugh it definitely conforms to Frohnmeyer balance, what is Shentrup balance?

Unfortunately it fails participation as any Condorcet method must. I think Condorcet is also incompatible with favorite betrayal, that may need checking.

@sarawolk I can envision a natural progression as: (1) implement straight approval, (2) eventually indicate the shortcomings of approval in guaranteeing election of Smith set candidates, (3) reform to include a ranked primaries to restrict to the Smith set before the final approval vote.

I agree it is not feasible to implement the kind of change needed for the mentioned kind of system all at once.

If approval were established somehow, the (rational, IMO) debate relevant to (2) and (3) would probably be about majoritarianism versus participation and maybe some tactical considerations.

Your point about tie-breaking is fair. For example, why not use Bucklin voting restricted to the Smith set, adjusting ranks to include only those candidates, which is similar to your suggestion. One major reason in that specific case is because it fails independence of clones.

I’m not necessarily just after a simple tie breaker. My concern is with reconciling majority cycles, which can destabilize the system. Something like approval in a second round enables the competing majorities to compromise more directly with full information. Otherwise a true majority may feel jilted by an arbitrary tie breaking rule.

Two-stage voting systems seem like a hard sell in the USA. However, I think a two-stage system is an extremely natural way to satisfy principles of majority rule and self governance.

My opinion is that an ideal single-winner system consists of a first round (or primary) of rank-based voting. If there is a Condorcet winner, no second round is needed. This can be decided easily by a run of B2R and checking if the winner is Condorcet.

Otherwise, the Smith set can be computed and made public. Once known, a second round of approval voting can be run over the Smith set.

Does this have any objectionable properties other than requiring two rounds of voting?

@gregw I think Condorcet is great when a Condorcet winner exists, but when one doesn’t exist it’s really troublesome. Ideally, we would have a method to check whether one exists without unearthing the Condorcet cycle that reveals the jilted majority upon the choosing of any winner, but that is essentially impossible.

I think it makes sense to do Condorcet//Approval, in two separate rounds, the approval round restricted to the Smith set. But two round voting outright is a difficult sell in the USA (even though two-round voting is pretty common all over the rest of the world…).

People try to put the two together in a single round vote, but the strategic incentives of casting rank and approval/score indications on the same ballot cause issues.

My personal belief is that this system of two-round voting for single winner elections, I.e. approval conditional on already knowing the Smith set, would be most ideal. I think actually implementing the approval aspect first however is an easier sell than implementing the Condorcet aspect first. I can envision a natural progression as: (1) implement straight approval, (2) eventually indicate the shortcomings of approval in guaranteeing election of Smith set candidates, (3) reform to include a ranked primaries to restrict to the Smith set before the final approval vote.

I feel even having rank/Smith-based primaries makes way more sense than what we have if the subsequent system is approval. There’s no issue with vote splitting in that instance, and it fits at least partially into the political system we already have (although this would also require substantial changes).

@gregw hm I’m just not sure how well-studied this method in particular is, as in, why it needs to be “most wins, fewest losses.” It makes as much intuitive sense as anything else, and it’s Condorcet so that’s fine.

Also it’s obviously susceptible to potentially unfortunate results when the Condorcet winner does not exist (which the above has ignored in their last step of the “how it works” section as “the candidate who beats all the others wins.”)

I still think rank-based methods are going to be much more difficult to gain firm ground on than approval. IRV got some traction but now it’s facing backlash (some rightfully so). Approval on the other hand seems relatively hard to argue against. I think it would yield a more lasting forward step.

@toby-pereira I’m sure the courts will conjure up whatever question-begging definition of vote they need to for whatever ruling they decided on beforehand. I think getting the reasonable notions settled on to facilitate progress without constitutional amendments will require more lawyering than only appeals to reason. It’s unfortunate that Maine’s constitution encoded plurality into its state voting law, I think it’s important to know what other states might have this same kind of language issue in their constitutions.