[EM] STV and Trees

Raph Frank raphfrk at gmail.com
Fri Aug 22 02:47:02 PDT 2008


On 8/22/08, Juho <juho4880 at yahoo.co.uk> wrote:
> On Aug 22, 2008, at 2:18 , Raph Frank wrote:
> > Thus, I don't see them as massively different ... the trees just add more
> > structure and reduce the freedom.
> >
>  The intention was not to reduce freedom. If a voter wants to bypass the
> default inheritance order as given in the tree he just ranks all the
> candidates (also other tools like names of some groups could be available if
> we want to go for maximum flexibility, e.g. "women", "Dublin", "under 30",
> "those who voted yes for X", "candidates that support Y"). Also declaring a
> vote to be just as written is ok (no inheritance if candidates on the ballot
> run out).

Well, I meant compared to candidate lists.  The candidate can set
his list up any way he likes under a candidate list system, however,
under a tree system, there are fewer valid choices.  This means
freedom is reduced.

However, it is likely that this freedom is not much use as a candidates
probably would just fill out his list semi-randomly as he gets to the lower
rankings.  The tree system helps here as it fills out all the rankings in a
standard manner.

>  Yes, this leads to STV votes that support equalities. Bullet vote to C1
> could become in effect C1>G1=G2=G3>P1=P2=P3=...

Yeah.

>  Yes, except that I think no flexibility is lost, so on the "negative" side
> there is only the added information in the poster listing all the candidates
> and that the voters are expected to roughly understand (well, it is maybe
> much easier to understand that than trying to dig out the opinions and more
> detailed affiliations of all the potential candidates oneself).

Well, the trees/lists might be used for national vote transfers.  In that
case, the voter cannot rank all the candidates.

>  Bullet voting could be common if the tree is informative enough. Also, in
> elections with multiple candidates the lost fractions could be relatively
> large.

Not sure that is a good thing, but if that is how the voters vote, then
that is their choice.  However, even with 2-3 choices, most of the
vote power would be assigned based on the voters direct choice.

Few candidates end up with multiple quotas, so most of your vote
goes to your first choice (assuming they get elected).

>
>
> > (Though, I would
> > allow a candidate to opt out).
> >
>
>  It probably is possible for a candidate to establish one's own party and
> not contribute and not benefit of the votes given to the party (or group).
> In most cases I'd expect the candidates to benefit of being a member of a
> party/group (even if the algorithm wouldn't favour large groupings like e.g.
> d'Hondt).

I meant opt out while not having to leave the party, though I
guess that is down to party rules.

> Candidates that are not members of any subgroups (at some level in the
> tree) could be grouped together to form a default list (unless they object
> this too).

They way I would work it is that the list they submit is constrained
by what groups they are members of.

If you are part of a party, then you must rank party members first,
but otherwise there is no restriction.

If you are part of a sub-group, then you must rank members of that
subgroup first and then the other party members.

> Well, maybe we just automatically give the "non
> left wingers" an option to form a corresponding grouping when we learn that
> a left wing grouping has been formed (and candidates may opt in and opt
> out).

Under the above rule, a member of the left-wing might rank as

L1>L2>L3>C1>C2>C3>R1>R2>R3

whereas someone who is unaligned might rank as

L1>R1>C1>R2>C2>L2>R3>C3>L3

(i.e. it actually means not aligned, rather than not left wing)

Someone in the right wing could rank

R1>R2>R3>C1>C2>C3>L1>L2>L3

This also raises an interest point, this would be a valid
right wing ranking

R1>R2>R3>C1>L1>C2>L2>C2>L3

It would meet the condition of ranking all members of
the right wing first, however, the left and centre wings
are not ranked as would be expected by a ring-winger.

This is probably not an issue as it is the early votes on
a list that actually matter.

> > The only rule would be that they must rank all party members before any
> > other candidate.
>  I didn't quite understand what the alternative to this would be.

Well, the alternative would be to allow party members complete
freedom on how to set up their lists.  This was talking about the
case where a party member doesn't take part in the tree structure.

However, I doubt parties would give candidates that much freedom,
so a specific rule is not required.



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