[EM] Venzke's election simulations

[Jameson Quinn]

2010/6/8 Kevin Venzke <stepjak at yahoo.fr>

> Hi Warren,
>
> --- En date de : Mar 8.6.10, Warren Smith <warren.wds at gmail.com> a écrit :
> > comments by WDS
> >
> > 1. I think using utility=-distance
> > is not as realistic as something like
> > utility=1/sqrt(1+distance^2)
> >
> > I claim the latter is more realistic both near 0 distance
> > and near
> > infinite distance.
>
> Why would that be? Do you mean it's more intuitive?
>
> > 2. It has been argued that L2 distance may not be as
> > realistic as L1 distance.
> > L2=euclidean
> > L1=taxicab
>
> That's interesting. I wonder what arguments were used.
>

I haven't seen anyone else argue this, but I've always found taxicab
distance more reasonable. Separate issue dimensions add linearly. If
somebody's going to put/take $3 in/from my left pocket and $4 in/from my
right pocket, that's a total of $7, not $5.

>
> > 3. Your "candidates bolted in place" (in locations selected
> > manually)
> > at some point needs to be replaced by an outer loop which
> > chooses
> > their locations from some distribution, and finds average
> > bayesian
> > regret over all candidate locations.
> > If I manually choose locations, I can probably make nearly
> > any method look like
> > "the best" or "worst" method...   that is
> > kind of anecdotal evidence
> > versus real evidence.
> > (Not that the anecdotes are uninteresting.)
>
> Well, it would be better to cycle over some of the locations, but taking
> the average over all possible locations would not be very good evidence
> either, since not all locations are equally likely.
>

OK, so you need to have some probability density function. But
systematically, not just by picking scenarios that seem reasonable.

>
> On the other hand if you select a scenario that seems likely to occur
> in practice, I think that is good and useful evidence, especially if you
> can't refute your conclusion by changing the scenario slightly.
>
> If you stick to reasonably realistic scenarios I really doubt you could
> find a way to make any method you like best or worst.
>
> > 4. your results look interesting but I do not know what a
> > lot of your
> > voting methods are, e.g. QR, VFA, SPST, C//A, etc.
> > Too abbreviated.
> > Need to supply a key.
>
> Of these:
> C//A: Elect the CW if extant, else the Approval winner.
> (Condorcet//Approval)
> VFA: This is what you have called Venzke Disqualified Plurality.
> Elect the FPP winner except that when more than half of the voters
> rank this candidate strictly last, instead elect the second-place FPP
> candidate.
> SPST: This is the same as VFA except that when the FPP winner is
> disqualified, his supporters' preferences are transferred, instead of
> simply electing the second-place candidate.
> QR: This is a new method by me called Quick Runoff. Elect the candidate
> with the most first preferences who does not have a full majority pairwise
> loss to the very next candidate in first-preference order.
>
> There is also CdlA (Conditional Approval) which is a method where voters
> gradually add more of their preferences as a result of disliked options
> being the vote leader in a "round."
>
> > 5. some conclusions, like RangeNS is better than IRV and
> > IRV-tr and C//A, look
> > fairly solid (happen in all your sims*); others, like
> > Bucklin is
> > better than RangeNS,
> > look inconclusive (happen in some of your sims, but reverse
> > happens in
> > other sims)
> >
> > *There was one exception, but it had very small regret for
> > all methods
> > other than MMPO and ApprZIS.
>
> I don't try to draw many conclusions at this point simply because not
> many scenarios have been analyzed. I mean four of the scenarios I posted
> were only 1D. And most of the utility differences were very small.
>
> Kevin Venzke
>
>
>
> ----
> Election-Methods mailing list - see http://electorama.com/em for list info
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.electorama.com/pipermail/election-methods-electorama.com/attachments/20100608/0e167f17/attachment-0001.htm>