[EM] British Colombia considering change to STV

[Juho Laatu]

In order to be a bit more concrete
and to complement my other mails I
draft here one approach to combining
STV like and shorter open list/tree
style ballots. The point is to see
what could be done when the number
of candidates grows large in STV
(and to try to take in what is good
in trees).

Let's assume a simple hierarchical
system with only two levels. The
parties, groups and candidates are
named as follows.

P1
  G11
    C111
    C112
    C113
  G12
    C121
    C122
P2
  G21
    C211
etc.

Each voter casts one ranked ballot
that may contain any of the above
named items.

Candidates have a default tree-like
order of inheritance. Vote C121 will
be counted as a vote to candidate
C121, group G12 and party P1. This
vote has the same meaning as vote
C121>G12>P1>ANYONE.

Vote C121>C211 is the same as vote
C121>C211>G21>P2>ANYONE. Note that
I assumed that the last ranked
candidate determines the order of
inheritance (unlike in the Maltese
proposals where the first preference
determined the party). If the voter
would like the first preference to
determine the order of inheritance
she could vote e.g. C121>C211>G12.

If one wants to determine one's
preference order within a group
one could vote C111>C118>C113. This
kind of votes may be quite typical.
Such votes may be easy to count in
some methods since it is clear that
they will support G11 and P1 in any
case.

We may allow also not giving any
support to the party of the last
ranked candidate. In this case the
vote could be C211>G21>P2>C111>ANYONE.

A bullet vote with no inheritance
could with this ballot style be e.g.
C555>ANYONE. Vote C555>C666>ANYONE
would be a traditional STV vote that
may become exhausted after C555 and
C666 have been eliminated (or elected).

Also votes where a group or a party
is ranked first are possible, e.g.
G12>G14.

The examples above show what kind of
votes would be possible in general.
Any parties and groups and candidates
can thus be ranked. In addition there
are some simple default inheritance
rules (last ranked candidate followed
by her group and party) that the voter
may overrun if she so wants.

I hope the intention and meaning of
this kind of votes is clear. From a
traditional STV point of view the
group and party names are actually
just abbreviations of candidates
in those groupings. Vote C111>G11>P1
does thus mean:
C111>
C112=C113=...=C119>
C121=C122=...=C131=...=C199

From a tree voting point of view the
idea is that voters can cast short
votes, and that they are offered a
basic structure where they can easily
see the affiliations of each candidate.
(Votes that list candidates from
different branches do break the idea
of seeing easily the power balance
between different branches a bit but
also parts of this benefit(?) can be
maintained.)

This approach may easily get too
complex for such traditional STV
ballot style where all candidates
are explicitly listed. In this case
we would need rows and columns also
for the groups and parties. One
easy approach would be to use code
numbers. A vote could be simple a
list of (maybe hand written) codes,
e.g. "13 63 23" where numbers could
refer also to groupings.

One could have large posters of
candidates instead of listing them
all in the ballot sheets.
02: P1
03:   G11
04:     C111
05:     C112
etc.
(maybe using some nicer graphics :-)

I'll skip the more detailed analysis
of the possible seat allocation
methods for now.

Juho