Voting system R&D (Re: 2017 update to the SPI voting algorithm for Board elections)

Ian Jackson ijackson at
Wed Mar 8 11:33:08 UTC 2017

Josh berkus writes ("Re: Voting system R&D (Re: 2017 update to the SPI voting algorithm for Board elections)"):
> Concordet is not a winning-faction-take-all system.  It is a "most
> acceptable candidate" system.  Which kinda makes this argument invalid.

Condorcet is a single-winner voting system.  SPI's homegrown
multi-Condorcet is a winning-faction-takes-all system.

Here is an example I posted in July, again:

Suppose there are 3 seats up for grabs, and red, pink, and blue board
candidates, 3 in each colour.  If the electorate votes along colour

    60 voters    blue > pink > red
    40 voters    red > pink > blue

Then the outcome with SPI's multi-Condorcet is:

    blue, blue, blue

That is precisely the winning faction taking all.
The outcome with STV is:

    blue, red, blue

> > I am trying to switch from "cool voting tech" to something boring.
> But STV is still a "single-winner" system.  Any multi-winner
> implementation of it we choose would *still* be experimental.

Seriously ?!

STV is not a single-winner system.  STV is the popular multi-winner
extension to AV (the single-winner system "Alternative Vote", which is
known in the US as "IRV").

STV is far from experimental.  Did you not spot that my draft
resolution refers to a UK Statutory Instrument (ie, government
legislation) from 2007 ?

> In fact, looking over your posts to spi-general and spi-private, I can't
> find one which does actually fully lay out what specific voting
> mechanics you're proposing.  I may have missed it because I was off
> spi-private for a month or so; can you please link your paper explaining it?

Please see my draft resolution.

I will repost it in a moment (with the numbering fixed).


Ian Jackson <ijackson at>   These opinions are my own.

If I emailed you from an address or, that is
a private address which bypasses my fierce spamfilter.

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