[EM] Holding byelections with PR-STV

[Jonathan Lundell]

On Sep 15, 2009, at 4:01 PM, James Gilmour wrote:

>> 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.

In fact, a special provision must be made to ensure that previously  
elected candidates remain elected in a countback. There are at least a  
couple of ways to accomplish this. It ends up being a subtle problem.  
(It's also worth noting that additional candidates might choose not to  
stand, or be ineligible to stand, in the countback, and would need to  
be marked as withdrawn as well.)

New Zealand apparently uses AV/IRV for "single-member vacancies",  
hardly ideal, for reasons that have already been adduced.

http://www.legislation.govt.nz/regulation/public/2001/0145/latest/DLM57125.html