[EM] Holding byelections with PR-STV

[James Gilmour]

> On Mon, Sep 14, 2009 at 4:19 PM, James Gilmour wrote:
> > The 'count back' procedure with STV-PR provides an alternative 
> > approach to the principle of preserving the proportionality determined 
> > at the previous main election.  Then the voters would get the 
> > proportionality they would have got at the main election had the 
> > member who caused the casual vacancy not stood at the main election.  
> > Where the elections are partisan, this approach would provide an 
> > incentive for the political parties to nominate more candidates that 
> > the numbers of seats they expected to win, so that they would have one 
> > or more "spares".  In Malta the main parties take this to extremes, as 
> > they both have sometimes nominated 12 candidates in some 5-member 
> > districts.

> Raph Frank  > Sent: Monday, September 14, 2009 5:22 PM
> I think, in the end, this is probably the best plan.  The 
> "spares" give an added bonus that voters get more choice.

Yes, this would be a very good side-effect of adopting the 'count back' procedure  -  and it's one (hidden) reason why some of us
are keen to see it introduced in Scotland.


> Under Meek, would this just be a matter of setting the 
> resigning candidate's keep value to zero?

Depending on the program you use, you don't even need to do that.  OpenSTV and some of the private UK versions of Meek STV have a
provision for "withdrawn" candidates.  You just set the number code for the 'withdrawn' candidate to its negative value (e.g. 2
becomes -2) in the second row of the BLT file and the program does the rest, passing over that candidate as though s/he had never
stood, I presume by setting a zero keep value at the beginning. (see "Ballots Menu" in OpenSTV Manual at
http://www.openstv.org/manual)

New Zealand is, so far as I know, the only country that uses Meek STV for public elections.  They do not appear to have any
provision for 'withdrawn candidates'.  They do allow multiple candidacies for specified hierarchies of elections, e.g. mayor
(first), territory (second), community (third).  So if a candidate is elected as mayor and also as a territory council member, they
declare an exceptional vacancy for the territory council and fill it separately.  They don't seem to use the 'withdrawn' feature  -
maybe it isn't programmed into their version of Meek STV.

In UK public elections candidates are not allowed to withdraw once the deadline for nominations has passed.  If a candidate dies
after the close of nominations but before the formal declaration of the result, the whole election for that constituency or ward is
declared void and a new election must be held within a specified number of days.


> Setting a candidate's keep value to zero should only increase 
> the vote totals of all the other candidates.  Thus, all 
> elected candidates would stay elected and Meek's method never 
> changes the keep values to eliminate an elected candidate.

The first statement seems logical, but I don't know about the second statement.  I don't understand how an elected candidate could
be eliminated  -  sounds like a contradiction of terms. 


> The problem would be that setting an eliminated candidate's 
> keep value back to 1 could bring an elected candidate below 
> the quota.  One option would be to set all "running" 
> candidates at the highest possible keep value such that all 
> elected candidates have more than a quota worth of votes.

I don't know what any of this means as I am not sufficiently familiar with the inner workings of Meek STV.

James

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