[EM] Free riding

[Juho]

On Aug 31, 2008, at 22:28 , Markus Schulze wrote:

> Juho wrote (31 Aug 2008):
>
> > Woodall free riding uses some irrelevant candidate that
> > is ranked first.
> >
> > Hylland free riding does not rank the favourite candidate.
> >
> > A third approach to free riding is to rearrange the
> > candidates to reflect the estimated probabilities.
> >
> > The true preference order of a voter is A>B>C>D>E>...
> > The voter expects A to be elected quite certainly.
> > Candidates B and C are less certain. The voter considers
> > B and C to be almost as good as A. Candidates starting
> > from D are considerably worse. As a result the voter
> > decides to vote B>C>A>D>E>...
>
> Suppose that you expect candidate A to be elected quite
> certainly. Then it is a useful strategy not to give your
> first preference to candidate A. However, it is also clear
> that it doesn't make any sense to rank candidate A below
> candidates you despise.

It may well be the best strategy to rank A below D in the example  
above if A will be elected almost certainly since the voter has an  
interest to guarantee that D will be elected rather than E. D and E  
might be even "despised" although of course the probability of  
finding this kind of a working (insincere) strategy decreases when  
the utility of D goes down.

> Therefore, I would summarize your strategy as a Hylland
> free riding strategy because you vote preferably for
> those of your favorite candidates who are less assured
> of election:

This particular example resembles Hylland free riding (it is an  
optimized version of it) but there could be also many other examples,  
some of which resemble e.g. Woodall free riding. Only in some special  
cases this method resembles Hylland. The point is to evaluate the  
probabilities and utilities of all candidates and vote accordingly.  
If looking for links to Woodall and Hylland, this approach in a way  
tries to generalize them under one framework.

Juho





		
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