[EM] How to make a summable version of STV

[Jameson Quinn]

This method leaves open the possibility for "candidate hijacking". Consider:
Sojourner Truth has 1000 votes who vote Truth > Douglass > Everyone. Robert
E. Lee has 1100 strategic voters who vote Truth > Lee > Everyone > Douglass.
They dominate the honest Truth voters, so Lee is considered to be Truth's
second choice. The Droop quota is 1900. Truth has no quota and is
eliminated; her 2100 votes pass to Lee; and Lee is elected. That kind of
pathology could cause a civil war.

Part of this is the LNH property of STV biting us. With a system that can
see past the top choice, you'd have 2100 votes which were essentially
half-Douglass-half-Lee. In systems like Schulze STV, that would at least be
helping Douglass, so the Lee voters would have to think twice about the
tactic. And in systems like RRV, that wouldn't be any more likely to elect
Lee than Lee's 1100 honest votes, so the tactic would be useless.

JQ

2011/7/23 <fsimmons at pcc.edu>

> Kristopfer.
>
> Look at it this way, the process of amalgamating the factions is a low pass
> filter that gets rid of some fo
> the noise.  So why not consider the resulting ballots as the "true"
> ballots, and the associated weights
> tell how many of them there are of each kinsd.  STV can be done with these
> new true ballots, Droop
> quotas and all.
>
> ----- Original Message -----
> From: Kristofer Munsterhjelm
> Date: Saturday, July 23, 2011 1:53 am
> Subject: Re: [EM] How to make a summable version of STV
> To: fsimmons at pcc.edu
> Cc: election-methods at lists.electorama.com
>
> > fsimmons at pcc.edu wrote:
> > > This is to illustrate a point that Warren has recorded on his
> > website> somewhere (I don't remember exactly where); namely that
> > lack of
> > > summability is not insurmountable.
> > >
> > > We start with the assumption that the voters have range style
> > ballots> on a scale of zero to six. [Seven levels are about
> > optimal according
> > > to the psychometrics experts.]
> >
> > I thought five was, not seven. Do you have any papers?
> >
> > > At each precinct the ballots are sorted into n piles, one for each
> > > candidate. The ballots in each pile are averaged together to
> > get a
> > > rating vector for each candidate. [At this first stage if a
> > > candidate shares (with k-1 other candiates) top rating on a ballot,
> > > then a copy of that ballot is sent to each of those candidate's
> > > piles, along with a weight of 1/k .]
> > >
> > > The precincts send the n candidate vectors, together with their
> > > respective totalweights to the counting center. For each
> > candidate a
> > > weighted average of the vectors for that candidate from all of the
> > > precincts is computed, and the total weight is taken as the
> > size of
> > > that candidate's faction.
> > >
> > > The STV computation is then based on these n almagamated factions.
> >
> > That would fail the Droop proportionality criterion. Just take
> > your
> > favorite example where Range fails it, then stick an universal
> > favorite
> > candidate X in front of every voter's vote. Now, there's only
> > one rating
> > vector - X's - and the averaging will smooth out any structure
> > beyond X.
> >
> > This is an extreme example, but the averaging could hide detail
> > in more
> > realistic ballot sets, too.
> >
> >
> ----
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