On Sep 10, 2008, at 4:21 AM, James Gilmour wrote:
Raph Frank > Sent: Wednesday, September 10, 2008 11:49 AM
Depends what you mean by "normal". There are at least six different
sets of rules for STV-PR now in use for public elections around the
world.
Fair enough. So they are just giving an official name to one
of them then?
I would not want to call it an "official" name. The core principle
of BC-STV already has a name (WIGM) in the academic literature
(Farrell & McAllister) and in literature associated with the
implementation in Scotland. However, there are lots more rules you
also have to consider for any implementation of STV-PR. Scotland
and Western Australia both have WIGM enshrined in their
legislation, but many of the other STV rules in these two
implementations are different. I think it would be OK to use the name
"BC-STV" for the complete set of election rules that will be used
for STV-PR in British Columbia, but they have yet to decide on
many of those rules (there is nothing about them in the BC CAER Tech
Report - it far from a complete specification)
The OpenSTV project <http://stv.sourceforge.net> implements a rather
large number of STV methods; the BC and Scottish implementations
differ in the number of decimal places to which the calculation is
carried out. It's difficult to fully specify a method, in the sense
that any two implementations that comply with the specification must
produce identical results under all inputs (modulo random tie-
breaking). Variations abound in surplus transfers, handling of ties,
and especially arithmetic precision and rounding.
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