[EM] So I got an email... / Binomial STV

[Kevin Venzke]

 Hi Richard,

Le dimanche 10 avril 2022, 03:21:38 UTC−5, Richard Lung <voting at ukscientists.com> a écrit :
> As recently written in my Winners or representation thread, I don't think the
> failure to achieve a Condorcet winner, as in Burlington justifies calling the
> preference voting system used, a mistake. It is an adverse consideration but not
> a definitive mistake. And as a 1 in 135 occurence, it is not highly significant
> -- not significant enough, in my opinion, to justify over-loading RCV with a CW
> veto on the result. I might compare it to leaving the scaffold on a building as
> a permanent feature.

This is a reasonable stance, but the "1 in 135" argument can be questioned given
that every RCV election is conducted under RCV's specific voting and nomination
incentives. That is, we can't be sure that the candidate selection would be the
same between different methods, or that voters would vote the same way after
accounting for strategic incentives.

Compare the argument that every known FPTP election also elects the Condorcet
winner, as far as anyone can really tell.

> RCV could be improved. -- I invented such a system, Binomial STV that works in
> single districts as well as multi-member districts (tho single districts do not
> work nearly as well as  [STV] multi-member districts). However I would not dream
> of employing an improved system (BinomialSTV) without test elections, which I
> would naturally like it to receive, before official employment.

You recently shared how to solve Binomial STV ("BSTV") for the three-candidate
one-winner case. Based on winner agreement rates, BSTV seems to be about as
different from RCV as possible. I wouldn't say all methods sit squarely between
them, but it's almost true that RCV and BSTV are closer to any other method than
each other.

This makes it hard for me to imagine what properties there could really be in
common between these two methods.

So I wonder, if you were to have the opportunity to conduct test elections for
Binomial STV, what standards would you use to assess whether the tests were
successful?

Kevin