[EM] Any unusual/bad/overlooked methods or lotteries? For a simulation

[Jameson Quinn]

I think that this kind of investigation of strategy in realistic monte-carlo
simulations is important. Two comments:

1. Do you plan to share your source code? I'd encourage you to do so,
preferably under some kind of open-source license (including just public
domain).

2. I've been thinking of how to extend Yee diagrams to show strategic
vulnerabilities. So far, I'm thinking of starting with a
interactiveone-dimesional Yee
diagram<http://zesty.ca/voting/voteline/> with
three candidates, and using method DNA to show separate strategic and
counterstrategic possibilities in separate lines. In those terms,
runoff-style methods (including my recently-developed MCA-Asset and GMCA)
are somewhat confounding, because a first-round strategy doesn't carry over
into the second round, so they effectively expand the range that the DNA
must cover to include both rounds (although I think that certain ballots,
such as A>B>C and then C>B>A, can be discounted).
For your simulation, I wonder if it would be possible to include such
methods, by assuming that voters would always be honest in the second
(two-candidate) runoff round? Of course, pushover strategies and
counterstrategies would become important for such systems.

Jameson

2011/3/8 Kevin Venzke <stepjak at yahoo.fr>

> Hi Kristofer,
>
> --- En date de : Mar 8.3.11, Kristofer Munsterhjelm <km-elmet at broadpark.no>
> a écrit :
> > > I'm working on another simulation. It is for
> > 3-candidate elections and
> > > allows these ballot types (if the method also allows
> > them):
> > > A (bullet vote)
> > > A>B>C (strict)
> > > A=B>C (tied at the top)
> > > A|B>C (middle candidate ranked but "disapproved")
> > >
> > > This should be enough to handle most rank or 2- or
> > 3-slot methods.
> > >
> > > The voters have some intelligence, and polling
> > opportunity, so a method like "elect the guy with the most
> > last preferences" should do just as well
> > > as Plurality.
> > >
> > > They can be a little superstitious, especially with
> > random methods: e.g.
> > > Random Ballot isn't perceived as strategy-free. And
> > there can be e.g.
> > > burial in IRV from voters who never managed to be
> > harmed by it.
> >
> > How is this superstition (on the one hand) and intelligence
> > (on the other) implemented?
>
> Well, I don't want voters to be superstitious. It's an accident. They are
> trying to find the best way to vote. But they may latch onto something
> that is not sincere, because they have no concept of that.
>
> > Also do voters who favor one of the candidates have greater
> > intelligence than those who favor others?
>
> I'm not sure where this thought comes from, but I think the answer is no.
>
> It is bloc-based, and a bloc votes together. So a large bloc could be
> said to be able to "coordinate" better. If there are few blocs (which is
> how I currently test it) it may not be very fair in this sense.
>
> > If you had a
> > computer that could strategize on behalf of every voter, you
> > would in effect have a DSV method, and the DSV method might
> > not be all that bad.
>
> It is sort of like that. It's based on polling. There's no difference
> between a poll and the actual election. So, voters have a good idea how
> other voters think they should vote, in the sense of how to respond to
> those votes. Voters may in effect decide on a "mixed strategy."
>
> It's possible to imagine that at the last minute voters in reality could
> decide to switch their polling vote to something else for the actual
> election. Could that be realistic? Those voters have to communicate their
> plan to each other without anyone else learning of it. My sim assumes
> that is not possible.
>
> > However, if one of the
> > parties/candidates are better at coordinating their voters
> > and executing strategy, they may snatch the victory from the
> > "honest" winner. Thus, the worst case in strategy might be
> > when all strategize (in mutually limiting scenarios like
> > Plurality's lesser evil situation), or when only some do,
> > and if you want to check the impact of strategy, you might
> > want to check both cases.
>
> I think I've mostly covered this, but let me know if not.
>
> I am very interested in what strategies are used. Four are detected:
> Compromise (involving reversal), compression, truncation (in the sense
> of bullet-voting), and burial. ("Push-over" strategy is possible but would
> be detected as compromise, and I'm not sure how to get around that.)
>
> Occurs to me that there's no "abstain" strategy, which might be
> interesting. A little tricky to add though.
>
> > > Anyway, I'm interested in methods that might pose a
> > challenge to my voters (such as perhaps deterministic
> > methods that fail majority favorite;
> > > I have very few of these), or methods that might
> > actually be good...
> >
> > Every positional method except Plurality fails majority
> > favorite. Range fails it as well, and Approval might if you
> > interpret it a certain way.
>
> Yes, all those are implemented, as well as strictly-ranked Borda. As an
> example of something odd: Once when playing with a simulation years ago
> I came up with the idea of taking the pairwise comparison between the
> approval winner and the candidate with the greatest opposition (approval
> or pairwise, I don't remember) to him. It sounded nice but it failed
> majority favorite.
>
> > You might also test Random Pair and Hay, if that's feasible
> > within your simulator. Both are strategyproof. Random Pair
> > picks two candidates at random and elects the one who beats
> > the other Pairwise. Hay is described here:
> http://www.spaceandgames.com/?p=8 and there's a (very
> > complex, cloneproof?) iterated version at
> http://www.panix.com/~tehom/essays/hay-extended.html .
>
> Random Pair is on the to-do list, but I don't think Hay is feasible if
> it requires a very fine ratings ballot. Can we do Hay with 3-slot ratings
> (normalization required)? I'll check.
>
> Another example based on Forest and Jobst's paper: What if the first-
> preference winner wins if he gets (say) 2/3rds of the vote, else Random
> Ballot? I'm pretty sure this would stump my voters with the number of
> polling iterations I currently use.
>
> Thanks for your thoughts.
>
> Kevin
>
>
>
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