(Fwd) STV and truncation

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(Fwd) STV and truncation

Craig Carey-2
Rob L. wrote [in elections-reform]:

>Steve Eppley wrote:
>[snip]
>> Doesn't the STV algorithm not attempt to transfer a ballot from a
>> winner's excess if it can't be transferred?  Won't it transfer other
>> voters' ballots, who have other candidates in their rankings,
>> instead?  This seems like it would be only a small tweak to the
>> algorithm, if needed.
>
>Hmm, this actually sounds like a dangerous tweak to make, if I
>understand you correctly.  A fringe candidate could end up getting
>the votes of people who never intended to vote for them.  Votes
>could "drift" very far from where the voter stopped ranking
>candidates.

Does fractional STV really throw away fractions of those ballots
which are truncated?  Is that better than keeping them and
transferring larger fractions of ballots which didn't truncate?

I'm not sure what you mean about the fringe candidates getting votes.
They wouldn't get votes of people who truncate them away.  Do you think
the fringies would be truncated away less than other candidates?

Perhaps you misunderstood my poorly written paragraph.

--Steve

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(Fwd) STV and truncation

Craig Carey-2
On Sun, 31 Mar 1996, Steve Eppley wrote:
> I'm not sure what you mean about the fringe candidates getting votes.
> They wouldn't get votes of people who truncate them away.  Do you think
> the fringies would be truncated away less than other candidates?
>
> Perhaps you misunderstood my poorly written paragraph.

Well, no, actually, I wasn't thinking too clearly yesterday.  It isn't
nearly as bad as I made out earlier, I don't think.  The problem that I
can see though, is that it in essence gives someone more than one vote.
Here's an example.

Candidate A needs 40 votes to make quota.  He gets 50, broken down as
follows:
40-A
10-A,B

Now, under your improvement, all 10 votes excess votes that actually have
a second candidate ranked would go to B, even though only 20% of A's
voters voted B.  Would the 40 voters be forced to put down a NOTA option
just to make sure that the fraction they are entitled to doesn't go
to B?

Let's say B had 40 votes prior to the transfer, broken down as follows:
30-B
10-B,C

Now, the 10 votes from A transfer to B, and B's 10 votes with a second
preference transfer to C.

I probably haven't gotten enough sleep prior to posting this, but do you
see my point?  The 10 votes could get a long way from home unless we stay
true to many voters' intention *not* to have their vote transferred.

Rob Lanphier
[hidden email]
http://www.eskimo.com/~robla