[EM] I need an example of Condorcet method being subjected

Jonathan Lundell jlundell at pobox.com
Fri Jan 22 08:32:45 PST 2010


On Jan 22, 2010, at 7:19 AM, Terry Bouricius wrote:

> Arrow never uses the word "spoiler" in his theorem (original nor revised 
> version). You may be thinking about his independence of irrelevant 
> alternatives (IIA) criterion. While this could be expanded to have some 
> bearing on the concept of "spoilers," it is not the same thing. Firstly, 
> Arrow used IIA (as well as Pareto consistency and non-dictatorship) as 
> desirable characteristics of a social ranking of options, not finding a 
> single winner (or winning set).

It's a point worth keeping in mind. We toss Arrow's Possibility Theorem around pretty loosely, when strictly speaking we should be talking about Gibbard-Satterthwaite, or (better yet) Duggan-Schwartz.

There are, of course, family resemblances.


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