[EM] (Fwd) STV and truncation

Kevin Hornbuckle kevinh at efn.org
Thu Apr 4 09:26:17 PST 1996

> >Steve Eppley:
> >> Question: Does STV permit a voter to rank two candidates equally?  If 
> >> so, how do the votes transfer?  (The reason I ask is because unranked 
> >> candidates are essentially ranked *equally* last.  Do they share a 
> >> fraction of the ballot if it's "transferred" to the unranked?  I 
> >> assume they don't.)
> >
> >In fractional STV no votes are transferred to the unranked
> >candidates. And yes, voters can rank candidates duplicatively. 
> >If I rank two candidates #1, each gets .50 of my vote. If one is
> >eliminated, the vote value to the other increases to 1.
> Doesn't this mean there's an inconsistency?  If leaving some
> candidates unranked is shorthand for ranking them equally last,
> shouldn't the truncated ballot be divided among all the unranked
> when it's time to transfer it?
> We've been using examples where we say {Nader,Clinton,Dole} is
> equivalent to {Nader,Clinton} in a 3-candidate race.  But these 
> two ballots would transfer differently.  I guess this means that 
> what's shorthand in one system (single-winner) isn't shorthand in 
> another (multiwinner).

Your conclusion is correct.
The goal of PR/STV is proportional representation.

As to your question about a truncated ballot, I'd have to think for a 
while on the political implications of your suggestion that after the 
truncation the remaing vote value (from a truncating voter) would 
transfer equally to all unranked candidates.

I think that would be the same as it is now: the truncating voter leaves 
it to nontruncating voters to decide who will meet the treshold thereafter.

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