On Aug 16, 2008, at 17:15 , Kristofer Munsterhjelm wrote:
I could see a kind of proxy front end to STV elections. I'm not
sure I'm convinced it would be a good idea, or even practical to
implement, but suppose that any person or group (including
parties) could register an STV ranking, and a voter could select
that ranking instead of ranking individual candidates. The
logistical difficulty would be in determining how a voter
specified their proxy, along with the possibility of ambiguity
deliberate or accidental ("Siera Club", "John Smith").
There's another difficulty with that idea, and one that Juho has
shown earlier, as related to the inheritance order of candidates in
the electoral system of Fiji. Candidates may put preferences in
different orders than you do, or come to an agreement with other
candidates to support each other.
To some extent, that could be fixed by publishing the ranking
beforehand, but one should still be aware of the difficulty.
I think that the simplest way of adding proxying to STV, user
interface wise, would be to have a delegation mark, where your
stated preference ordering overrides that of the candidate. For
instance
A > B* > C (rest left blank)
with * as the delegation mark, and B having the preference ordering
B > E > F > C, would give
A > B > E > F > C
This vote could be alternatively interpreted as A > B > C > E > F.
by substitution, whereas
A > C > B*
would give
A > C > B > E > F
since the A > C preference that the voter manually stated overrode
the F > C preference of candidate B.
Paradoxical preferences could be resolved by highest ranked first. If
A > B* > C*
and B prefers D to E, but C prefers E to D, then the final ordering
prefers D to E since B is ranked above C. An even more
sophisticated version could run a single-winner social order
election for equal-ranked candidates, so that
A > B* = C*
gives A > (result of social ordering, according to single-winner
method, for those candidates for which B and C gave any preference)
On the other side, a simple version of default or explicitly
indicated vote completing preference order would be to use the tree
structure (and only one star (maybe use first or last listed
candidate by default) to indicate which branch of the tree to use).
Juho
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