[EM] independence form covered alternatives is incompatible with monotonicity

Kristofer Munsterhjelm km-elmet at broadpark.no
Sat Jul 17 00:59:03 PDT 2010


fsimmons at pcc.edu wrote:
> Suppose that we have a method that satisfies independence form covered alternatives, and that gives 
> greater winning probability to alternative B in this scenario
> 
> 40 B>C>A
> 30 C>A>B
> 30 A>B>C
> 
> than in this scenario
> 
> 40 D>B>C
> 30 B>C>D
> 30 C>D>B
> 
> as any decent method would.

Could one make a deliberately perverse method that would return bad 
results but would technically pass both independence from covered 
alternatives and monotonicity, or is it possible to make an absolute 
incompatibility proof?



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