[EM] Couple of comments (AMA, Why the fuss)

[Kevin Venzke]

Hello,

Colin wrote:
> Their specification doesn't say what to do if two pairs have equal margins, although other
> forms of tie are at least vaguely described. I assume "there is a tie" means "the margin is
> zero", but the language is slightly misleading. Maybe whenever two pairs had equal margins
> the AMS resorted to a coin toss between all candidates.

Incidentally I think this is a considerable advantage of Schulze, that no matter which
approach you use, i.e. the beatpath algorithm or the Schwartz sequential dropping one, you
are able to go through the calculation a single time and you will know whether ultimately
there is a tie and who was in it.

I recently made a calculator that tries to show the steps to solve Ranked Pairs and River
and I couldn't come up with a satisfying way to dedupe all the possible ways that one could
traverse the propositions when there are tied strengths, and potentially many. I settled on
showing up to two traversals per possible winner.

Kristofer wrote under "Why all the fuss?":
> (Of course, it's not that easy: someone has to actually implement the method -- and the 
> simulations!)

Yes, implementing a complicated method can take some time, and I'm often unsure of the
prospects for a method to be good in some way. (This might even cause me to implement it
wrong due to bad intuition.)

I've seen skimming the recent posts that Forest is proposing a number of methods where
you're pretty much going to look at all the pairwise contests, and there are a number of
points within the course of following the algorithm where the method can take a turn and
lead to a change in outcome. I feel pretty confident at least that such a method, from a
burial incentive standpoint, is not going to be very interesting to Kristofer. It might
work for me, that's true.

One thing I could do is provide a bunch of examples on what methods look like in my
framework, taking the form of a Python 3 class, and then people could just send me methods
if they want. I'm not sure if there would be any takers for that. It would probably be more
interesting if I was maintaining and publishing a big list of results, which at the moment
I'm not. (Partly due to the sensitivity of results to scenario parameters.)

The idea of making some new visuals is interesting. I would like to somehow map the
correlations or apparent trade-offs present in methods' compromise, burial, and truncation
incentive. That's seemingly a 3D plot though.

Kevin
votingmethods.net