[EM] IRV in San Francisco

[Dave Ketchum]

On Fri, 12 Nov 2004 13:06:23 -0500 Eric Gorr wrote:

> At 7:44 AM -0800 11/12/04, Justin Sampson wrote:
> 
>> On Fri, 12 Nov 2004, Eric Gorr wrote:
>>
>>  > Well, it will cause IRV to fail the Independence of Clones 
>> Criterion and
>>
>>>  thereby be subject to a spoiler effect again.
>>
>>
>> Doesn't IRV suffer from spoiler effects anyway?
> 
> 
> Depends.
> 
> The method itself passes the ICC, so spoilers cannot come from there.
> 
> It, of course, fails IIA (as all ranked ballot methods do), so spoilers 
> in this context still exist. Of course, since no ranked ballot methods 
> pass IIA, talking about spoilers in this context is not very interesting.
> 
> Are there more directions from which spoilers can appear?
> I am currently not aware of any.
> 
I do not keep up with the alphabet soup, but IRV and Condorcet disagree as 

to winner in the following, and I see Nader as a spoiler for IRV:


40 Bush
35 Nader, Kerry
25 Kerry

Condorcet sees 35 Nader as ignorable and then 60 Kerry vs 40 Bush

IRV discards 25 Kerry; then sees 40 Bush vs 35 Nader.



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  Dave Ketchum   108 Halstead Ave, Owego, NY  13827-1708   607-687-5026
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