[Election-Methods] USING Condorcet

[Kevin Venzke]

Hi Juho,

A quick response.

--- En date de : Mar 8.7.08, Juho <juho4880 at yahoo.co.uk> a écrit :
> Ok, this is a good concrete example scenario. The votes are
> of course  
> simplified. Surely there would be also considerable number
> of other  
> kind of opinions than these three. 
> But let's see first where these simplified votes could lead to.
> 
> Sincere opinions:
> 45 A>B>C
> 40 B>A>C
> 15 C>B>A
> 
> It seems that C is an extremist candidate (at the B side of
> the  
> political map since they prefer B over A). In line with
> this  
> explanation it is natural that A supporters prefer B over
> C. It is a  
> bit more strange that all B voters prefer A over C. Maybe C
> is so  
> radical that all others hate him/her. (The nature of the
> scenario  
> will however stay quite similar even if there were also
> some B>C>A  
> voters.)
> 
> The A party or A proponents have a plan to bury B under C.

I don't know about this. Is it necessary to have a plan? This isn't like
pushover strategy where only a certain percentage of the faction should
vote in a certain way, or risk failure. You're not going to be the "one
strategizer too many."

> What if the A proponents manage to get the required 89%
> strategic  
> votes or more to support their strategic plan? Then the C
> supporters  
> can use a compromise counter strategy and rank B first. If
> more than  
> 5 of the C supporters will use this strategy that will
> nullify the A  
> strategy even if they manage to get 100% of the A
> supporters to  
> follow the strategy. Less strategic C voters needed if less
> than 100%  
> of the A voters will follow the strategy.

Nullification is no consolation though, because there is nothing to fear
from it. You may as well say that some of the C voters strategically
vote for their last choice A in order to make A a majority favorite so
that A voters' strategy does nothing.

> If the method uses winning votes then the B supporters may
> also use  
> truncation as their counter strategy. 30 votes or more (out
> of the  
> 40) needed. That would be a threat to elect C if A voters
> will apply  
> the strategy.

Yes. If WV or Condorcet//Approval is used I don't believe there would be
a problem, since truncating the worse frontrunner would be both natural
and effective. (Actually, as long as truncation is allowed I believe
voters won't rank the worse frontrunner anyway, even if you tell them they
ought to or safely can.)

> Theoretical examples on paper give complete information of
> the  
> opinions and allow complete control of (uniform) voter
> behaviour, and  

My claim is that the former is plausible (at least the information will be
complete to the extent necessary) and the latter unnecessary, when
it's predictable that truncation will not be used.

> (One more reason why A voters should not use burial
> strategy is that  
> if C is stronger than expected then their strategy might
> also lead to  
> electing C instead of B.

If there's any possibility of this scenario, I don't believe people would
use burial.

Kevin Venzke



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