[EM] Hybrid/generalized ranked/approval ballots

[Peter Zbornik]

Hi Kevin,

answers and questions in the text of your email below.

Best regards
Peter Zborník

On Thu, May 26, 2011 at 5:12 PM, Kevin Venzke <stepjak at yahoo.fr> wrote:

> Hi Peter,
>
> You are right. Your treatment has been discussed for, I suppose, 15+ years
> on this list, and your reasoning for it is a major factor.
>
> --- En date de : Jeu 26.5.11, Peter Zbornik <pzbornik at gmail.com> a écrit :
> Kevin Venzke wrote in his mail below (May 9th 2010):
> 35 A>B
> 25 B
> 40 C
> A will win. This is only acceptable when you assume that the B and C
> voters meant to say that A is just as good as the other candidate that
> they didn't rank. I don't think this is likely to be what voters expect.
> It seems misleading to even allow truncation as an option if it's treated
> like this.
> End of quote
>
> you wrote:
> Well I think think that as a voter I would indeed be pleased if A would win
> and not C.
> If the completion system above would be used (i.e. A=B would be counted as
> 0.5 win for A vs B and 0.5 win for B vs A), then there the winner would
> always be the same disregarding which of the following winning criteria was
> used: winning votes, losing votes, margins or quotas.
>
> [end quote]
>
> Can you explain why as a voter you would be pleased if A won and not C?
> What reason do these ballots give us to suppose that A is a better
> candidate than C? Does the fact that A voters have a second preference
> make A a better candidate?


I aggree that the issue of incomplete ballots or partially blank votes as I
would call it, is not as clear cut as I thought in the post above. Please
refer to the discussion in the email to Kristoffer.


>
> In other words: Electing A violates Woodall's Plurality criterion.


I aggree.

>
> I don't find the election of C to be very good, but it is better than
> electing A.
>
>
> [resume quote]
> Let us analyse the example in your mail below. We apply the Schulze
> beatpath with different criteria (biggest win, margins and ratios):
> [end quote]
>
> I think you forgot Schulze as it is usually done: Weakest biggest loss.
>

With "weakest biggest loss", do you mean losing votes (
http://m-schulze.webhop.net/, page 7)?


> In that case you elect B, which is my preference. This minimizes the
> number of voters who feel the outcome was spoiled by one of the
> candidates.
>
>
> [resume quote]
> What are the pros and cons of the approach above?
> Prima facie it seems that the treatment of hybrid ballots above could solve
> the problem of bullet voting, but I am far from sure.
> [end quote]
>
> I still stand by what I originally said, that I don't believe voters will
> expect or like this treatment of truncation. Voters will expect that if
> more than half of the voters say X was better than Y, then that's the
> important contest, and Y should certainly not win. The presence of some
> weak candidate Z should not cause the method to be confused about X vs.
> Y.
>

Yes, that depends if the voters think Woodall's plurality criterion is
important. I think the goal of STV elections should be proportional
representation, which might (or might not) be hampered by the plurality
criterion. See the discussion in my response to Kristoffer's email.


>
> You will tell them you're only doing this for their own good. But I
> think there is an incurable disconnect between what truncation seems to
> mean and what it actually does mean in your scheme. I think that when
> you use this scheme, truncation should not be allowed at all: You should
> have to explicitly rank all the worst candidates equal, if that's how
> it's going to count.
>
> Otherwise, you are going to sometimes be electing candidates on the basis
> of equal rankings that were cast in the form of voters completely ignoring
> a candidate. That seems like an opportunity to criticize the legitimacy
> of the winner.


With this I do aggree.

>
> Experimentally, in simulations: When you treat equal-ranking as split
> votes, voters will have to compromise more often, instead of just
> compressing the top ranks. This suggests weaker, non-frontrunner
> candidates are more likely to be best advised to drop out of the race,
> because their presence is more likely to harm the voters that support
> them.
>

Could you please send me a link to these simulations?


>
> Kevin
>
>
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