[EM] Clone proofing Copeland

Juho juho4880 at yahoo.co.uk
Sun Jan 7 13:23:32 PST 2007

Ok, the method that I proposed is not as defensive against burial as  
the original one. My target was just to make the method better with  
sincere votes (not to seek the ultimate most strategy resistant  
method). I'll come back with this method and also some other variants  
when I find some more time (they require some more processing, I'm  
not quite happy with the one that I proposed either although it shows  
my intended direction very well).

But I'll however mention some random observations that the example  
that you used made me think.
- One could also claim that these votes are a result of strategic  
voting but in another way than what you described. Instead of having  
49 voters that strategically changed their vote from B>A (or B) to  
B>C one could have had just one voter that strategically changed her  
vote from C>A to A>B. As a result numbers 25 and 26 were swapped and  
counting the first place votes gives a different result. The  
strategic voter was not able to get her #1 favourite but she could  
easily help her #2 favourite become elected.
- In addition to strategies one of course also has to pay attention  
to the sincere votes. What would be the best candidate to elect if  
the votes in the example were all sincere? There is thus always a  
balance on how much one needs to protect against strategic voters  
since all such changes in the methods (in most cases) make the  
achieved utility with sincere votes a bit worse. If there is no  
significant risk of strategic voters spoiling he election => use  
methods that pick good candidates with sincere votes. Lots  of risk  
=> use all necessary means and modify the method so that the impact  
of strategies stays tolerable. Different rules apply in different  
voting situations (e.g. public large scale elections vs. contentious  
elections among the members of this list :-) ).

Juho Laatu

On Jan 2, 2007, at 17:37 , Chris Benham wrote:

> Juho wrote:
>> How about "the smallest number of ballots on which some  
>> alternative  that beats A pairwise is ranked higher than A"?
>> Juho
> No, that would have nothing like the same strength or resistance to  
> Burial.
> 26: A>B
> 25: C>A
> 49: B>C  (sincere is B>A or B)
> The Simmons method narrowly elects A (the sincere CW), while your  
> suggestion easily elects
> the Burier's candidate B.
> Chris  Benham

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