[EM] Re: CIBR examples, and its CC failure

[Ken Kuhlman]

On 5/27/05, Araucaria Araucana <araucaria.araucana at gmail.com> wrote:
> 
> 
> I've seen this Borda-advocate logic before. 


Not surprising. As I stated, it's a summary of an explanation made by Saari. 


Eliminating 'symmetric' votes is just eliminating votes. 


No vote has been eliminated.. some have cancelled. To again summarize Saari, 

this is equivelant to telling a husband and wife team with diametrically 
opposed views that it's OK if they don't vote, because the election method 
in 
use understands that their views cancel eachother out. 

If you eliminate C from the original election, the voters prefer A to
> B, Borda or Condorcet. But introducing C to the ballots doesn't 
> change the Condorcet winner, just the Borda winner. 


In Condorcet's classic example, this is true. But it's just as easy to 
identify profiles where if a candidate drops, the Condorcet winner changes
but the Borda or winner don't. 

Borda is far more prey to weird IIA-violation effects than Condorcet. 


By "IIA-violation effects" I assume you mean candidate dropping? If so, 
please give me a reference where this is proven. 


I've also been following your CIBR arguments. It seems to me that
> you're setting up a straw man for Borda, since clone independence is 
> not Borda's worst failing. Burying is much worse and you haven't
> addressed that at all.


Either you're in the minority in considering burying to be Borda's worst 
failing,
or the random sampling of Borda criticism I've read has been strangely 
skewed.

Regardless, burying was the first problem identified with Borda (Borda, "My 
system 
is only for honest men,") and I do take it seriously. Fortunately, it's 
untrue 
that I "haven't addressed it at all." 

If supporters of a strong candidate strategically rank a weaker candidate 
higher than 
a close competitor, they would have to give the weak candidate enough 
support to 
make it a Borda winner over the competitor they're trying to "bury." 
Otherwise, the 
weak candidate will be certain to be eliminated when paired with the close 
competitor. Even if they're able to do so, the "weak" candidate would then 
become
a serious contender to the candidate that's being "aided" by the burying 
tactic, and 
so the strategy is likely to backfire. 

Further, the voter block that's attempting the burying strategy is likely to 
create a 
clone in the process, which would cause the weak candidate to be eliminated
immediately, gaining the block nothing. 

-Ken
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