Friday, February 24, 2012

Do We Have Consensus?

Voting and consensus are at the heart of the Ethosphere. It will be essential to choose the right voting algorithm(s), focus on transparency, and build and maintain a high level of trust in the consensus mechanics. The goal is that every user will come to trust the system so that, even after losing a contentious vote, there is confidence that the outcome of the procedure was, in fact, a true reflection of the will of the team, taking into account the relative reputations of the members.

This will be a tall order, given how little trust there is in the real life voting procedures and mechanisms currently used to decide issues and elect leaders throughout the world. There are major issues, both technical and political, with these real world systems, many of which Ethosphere has a unique opportunity to remedy given the benefits of its smaller scope, electronic nature, and years of research and thinking about the nuances of social choice.

In particular, the Ethosphere improves upon many other social choice systems in at least four major ways:

  1. Voting Algorithms - We will choose a voting method that is less susceptible to strategic/dishonest voting and fairer with respect to minority opinions.
  2. Rational Representation - Member reputation provides an excellent opportunity to balance the need for involved, knowledgeable electors with a fully-participatory, direct democracy.
  3. Protection of Minorities - The temptation of factions to secede from a teamspace because of a losing, perhaps contentious, vote will usually be outweighed by the benefits of staying with the team.
  4. Transparency - Every vote can be examined and audited by any member.

Voting Algorithms

There are basically two types of decisions that will often need to be made in Ethosphere: single choice and multi-choice decisions. A single choice decision asks the question, is this prop acceptable to a majority of the members of a teamspace, where "majority" means reputational majority. A multi-choice decision is involved in choosing from among a number of alternate props.

The single choice, yea/nay votes are the easiest to get right, in so far as the voting algorithm is concerned. Almost any algorithm, including the crusty and hopelessly broken plurality method in use today in the U.S. and many other places, reduces to something that works just fine for single-choice elections.

Multi-choice elections are mathematically and socially more challenging for the voting mechanisms. There is a ton of research and opinion about voting procedures and consensus algorithms, going all the way back to the ancient Greeks and including such luminous names as Plato, Daniel Bernoulli, Daniel Webster, Thomas Jefferson, James Madison, Bertrand Russell, and John von Neumann. Ironically, it seems completely impossible for experts, even professional mathematicians, to reach consensus on what is the best way to reach consensus.

There are literally dozens of different algorithms and hundreds of variations in use today. Rival web sites devoted to one method or another contain pages and pages of calculations, simulation results, and oratory wherein otherwise rational mathematicians and social scientists argue like school girls over who has the cutest boyfriend. But they all seem to agree on one thing: the first-across-the-bar plurality procedure still being used today in many places is one of worst, if not the worst possible choice.

The Ethosphere draws from two of the leading contenders among modern voting procedures: Instant Runoff Voting (IRV) and Range Voting (RV). We will describe each of these briefly in future posts, but if you wish to learn more about them and you don't mind sifting through a whole lot of silly bickering along the way, you should visit and which are maintained by the respective advocacy groups.

For both these voting procedures, the ballot is a little different from, and slightly more complicated than, the simple one-chit-for-my-favorite type of ballot we are used to seeing in plurality elections.

Strategic Voting

These voting algorithms are vulnerable to so-called strategic, or dishonest voting whereby, given advanced information about the relative strength of the candidates, a member can sometimes help its preferred candidate more by ranking them in a way that doesn't reflect the member's actual preferences. Obviously, this is an undesirable characteristic, but unfortunately there is a kind of uncertainty principle for voting systems, called Arrow's Impossibility Theorem which essentially says all voting systems are vulnerable to this kind of strategic voting to some degree at least. In other words, voting theory is a branch of game theory. So be it.

Because of this, the Ethosphere should discourage dissemination of information about a vote's partial outcome before it is closed. In fact, it should not be possible for any member to know who has voted, or how, until the vote is finished and the winner is determined. Of course, this doesn't prevent unofficial, but perhaps accurate, polling of members via messaging or email. Those annoying pundits, pollsters, and prognosticators who hover around real-life elections will likely evolve in the Ethosphere as well.


  1. Hi; I'm a range voting supporter who got here following your recent IRV-explainer entry, and then backtracked to your previous voting entries.

    First, a comment about what Arrow says. It's not about strategy. Arrow assumes honest rank-order preferences, and 5 axioms that seemed to him to be basic requirements for any voting system to ever have a chance of reaching a fair outcome. The conclusion is that there's no possible way to do it. Strategic voting makes it worse, but it's not necessary to raise it.

    Interestingly, since Arrow assumes honest *rank-ordered* preferences, Arrow's theorem does not apply to range voting and its cardinal preferences. And indeed, we range supporters have argued that it meets all 5 of Arrow's axioms.

  2. Thanks for your comment, Dale. I'm no expert on voting theory, so I appreciate your input. I'm coming at this from the practical necessity of finding a reasonable, workable online voting procedure for use in the specific context discussed here, reputational voting.

    I guess I was thinking of the monotonicity requirement in Arrow's theorem. Is it a gross over-simplification to paraphrase the result like this:

    Every "reasonable" preference function (e.g., it takes into account everyone's individual preferences, it always produces a complete result, and it ignores irrelevant alternatives) must admit the possibility that an individual who ranks his preferred candidate higher might actually hurt that candidate's overall societal ranking.

    I see your point that the theorem doesn't distinguish between deliberate, informed strategic voting and accidental non-monotonicity.

    Since I'm discussing choosing a single winner from a list of alternatives here, should I have cited the Gibbard-Satterthwaite theorem instead? It doesn't have the same ring to it, does it? ;)

  3. BTW, tomorrow's post will have a similar, 30,000 foot overview of range voting. And a later post will describe a homegrown (I think) combination of the two I call harmonic range voting. I would appreciate your critique since, as I said, there is a non-zero possibility I am full of s**t about this stuff.

  4. It's starting to get the idea across, but it's maybe a bit incomplete.

    Let's get one thing out of the way first: No (known? used?) non-dictatorial (N-D), deterministic ranked-order method passes independence of irrelevant alternatives (IIA). While what you said doesn't strictly state it, it does imply that a N-D & monotonic (Mon) method would pass IIA, which would be false (proof by example: IRV is N-D & ~Mon, but also ~IIA.)

    Secondly, it's not completely accurate to say, as you did, that N-D & IIA -> ~Mon. The truth is actually a bit worse. N-D & IIA imply that even if *every* voter preferres A over B, the voting method could still elect B. This is called unanimity or Pareto efficiency, and it combines monotonicty with non-imposition.

    I've found that Wikipedia's page Arrow's impossibility theorem is actually a pretty darn good piece of work on the subject (and referred to it more than once while composing this reply.)

    As for using G-S instead (despite the cumbersome name ;) it does explicitly refer to tactics, so yes, that might be the one you'd rather to go with.

    Incidentally, range voting passes G-S for 3 voters (but not for 4 or more)

    I should admit that I'm not truly an expert either; I read William Poundstone's "Gaming the Vote" in December of 2008, and have only been studying this stuff in depth (but still just as a hobby) for a bit longer than that. If you're interested, I blog about this very topic at The Least of All Evils.

    Heading off to read your range voting overview now :)