[EM] IRV vs Plurality (back to the pile count controversy)

[James Gilmour]

Abd ul-Rahman Lomax  > Sent: Friday, January 22, 2010 5:53 PM
> > At 03:57 AM 1/22/2010, James Gilmour wrote:
> >This
> >second set of rules are those that prescribe the transfer of votes
> >"to the bitter end", i.e. even after the winners have all been
> >determined.  Under this rule a ballot marked "A" would be treated 
> >differently from a ballot marked "A>B": at the last possible
> >transfer, the "A" ballot would become 'non-transferable 
> >(exhausted)', but the "A>B" ballot would be transferred to A.
> 
> You mean transferred to B, of course.

Apologies - my example was incomplete.  To illustrate this stupid rule properly, I should have posited two candidates, A and B, (or
just two left after all others have been eliminated), with A the winner.  Then consider two ballots, one marked B and the other
marked B>A.  In the last round of a count under the "to the bitter end" transfer rule, the ballot marked B would be
'non-transferrable (exhausted)', but the vote on the B>A ballot would be transferred to A.  It is illogical to treat these ballots
differently in an STV (contingency choice) election and it offends the underlying concepts of 'Later No Harm' to transfer the B>A
ballot to A.


> >This second rule is, of course, a stupid rule but that does not mean
> >it has not been implemented in some jurisdictions, including,
> >sadly, Scotland.
> 
> Not stupid, precisely because of the difference between A>B and A. 
> The former is an acceptance of the last listed preference, the latter 
> is not. It makes a difference if a majority is required. Not if it is 
> not, though it might make a difference with some methods. But not IRV.

But my comments were exclusively in the context of STV elections (IRV, STV-PR, RCV).


> >  It is also a highly undesirable rule because it means that my vote
> > could, in some circumstances, be transferred to
> >the candidate I deliberately ranked last in the lowest possible 
> >place, e.g. 12th out of 12 candidates.
> 
> Basically, if there are as many ranks as candidates, don't vote for 
> that last one! That's your choice, unless full ranking is required, 
> in which case you *can't* vote the truncated vote and it is 
> irrelevant if it's counted or not.

That's why when running an STV election where we can use "write in" boxes for all preferences, I always provide one fewer preference
box than the number of candidates (as I see you recommended in a later part of  your post).  But all of our ballots for public
elections have the candidates names printed on them.


> >   Following on from the
> >concept of 'Later No Harm' (which underpins the whole of contingency
> >voting, as in IRV and STV-PR), it is very important to be able
> >to give a voter the absolutely assurance that under no circumstances 
> >will her vote ever be transferred to the candidate she has
> >ranked 12th out of 12.  Sadly, the stupid "transfer to the bitter 
> >end" rule undermines this.
> 
> Only because of voter ignorance, an ignorance which has sometimes 
> been encouraged by activists.

No, not at all.  This is a piece of nonsense that some have introduced into STV counting, especially since electronic counting
became available.  It does not feature in any of the long-established versions of STV counting rules promoted in the UK.

James Gilmour


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