Re: Constitutional amendment: Condorcet/Clone Proof SSD vote tallying

[Andrew Pimlott <andrew@pimlott.net>]

On Sun, May 25, 2003 at 02:59:48PM +1000, Anthony Towns wrote:
> From a voting nerd point-of-view, we're not really running a simple
> Condorcet vote here, we're actually running two votes simultaneously. One
> is an approval vote, where we mark every non-default option as either
> approved or not-approved; and we require that a particular proportion of
> the developer body approve each option, and that more developers approve
> it than do not.  The other is a Condorcet vote, evaluated on the approved
> (non-default) options. Only if there are _no_ approved options does the
> default option win, which is to say, does the the vote get discarded.

This is a good way to frame the proposed method.  I think it also
provides the best ways to attack it:

1.  Approval voting has obvious incentives to strategic voting.  The
    electionmethods people consider it clearly inferior to Condorcet
    voting, in part for this reason.  Specifically, why don't you
    think this is a problem with the proposed method?

    The closest I've seen you come to addressing this was to say
    that strategically voting something unacceptible is "kind of
    petty".[0]  But there is no shortage of evidence that people
    vote strategically, and I'm sure many of them consider it
    perfectly justifiable.  What would make it petty in the context
    of Debian?  I can see possible answers to this, but I think it
    remains a very hard question.  For example, consider the biases
    introduced if there is a contingent of "moral" Debian developers
    who vote sincerely, and another of "pragmatic" developers who
    vote strategically.

    I should note that while the possibility of strategy is itself a
    problem (in that it makes it harder to decide one's vote, and
    may pose a moral dilemma to some), the more serious implication
    is that it undermines the goals of the method.  So a win over
    the default option may imply that an option is "generally
    acceptible", but the converse does not follow.  Strategy
    basically weakens any rationale for a method, including the
    worthwhile ends that you have set out.

2.  In combining two methods "in serial", you create a
    discontinuity.  As the example to which you replied shows, one
    vote can be the difference between a "landslide" for A (in round
    two), and elimination in round one.  This raises questions of
    fairness, and makes it difficult to speak meaningfully of a
    margin of victory.

    You could argue that the "result" of an election is only the
    winner, and that concepts of continuity and margin are
    irrelevant.  But I think this violates most people's intuition
    about elections.  If the example actually happened, I suspect
    many people would be angry and feel cheated.

    You could (and I think you have) also argue that these
    discontinuities don't happen in realistic scenarios.  But in
    making this claim, you have implicitly ignored problem 1.  I
    think that if many voters use strategy, such outcomes are
    plausible (perhaps not for the quorum case, but for the defeat
    by the default option case).

Andrew

PS.  Although I haven't participated in the discussion recently, I
have followed it, and I honestly don't think the above have been
addressed.  So please give me a pointer if you think they have.

[0] http://lists.debian.org/debian-vote/2002/debian-vote-200212/msg00101.html