[EM] A Comparison of the Two Known Monotone, Clone Free Methods for Electing Uncovered Alternatives

[fsimmons at pcc.edu]

Chris,

You are right that since Chain Climbing does not satisfy IPDA, neither does the method that takes the 
parwise victor of it and the Covering Chain winner.  I was more thinking out loud than pushing that idea.

Do you think that Approval Sorted Pairwise and the Covering Chain process are simple enough for use in 
a public proposal?

Happy New Year!

Forest

----- Original Message -----
From: "C.Benham" 
Date: Tuesday, December 28, 2010 7:27 am
Subject: A Comparison of the Two Known Monotone, Clone Free Methods for Electing Uncovered 
Alternatives
To: em 
Cc: Forest W Simmons 

> Forest Simmons wrote (16 Dec 2010):
> 
> > Chris,
> >
> > Thanks for reminding me of Approval-Sorted Margins. The 
> covering 
> > chain method applied to the list obtained
> > by approval sorted margins certainly has a maximal set of nice 
> > properties, in that any additional nice
> > property would entail the loss of some highly desireable property.
> >
> > Do you think it is better, in this context, to base approval 
> on 
> > ranked-above-last, or by use of an explicit
> > approval cutoff marker?
> 
> 
> Forest,
> 
> I like both versions. I think the version that uses an approval 
> cut-off (aka threshold) marker is a bit more
> philosophically justified. (It seems arbitrary to assume that 
> ranked-above-bottom signifies "approval", or
> putting it the other way, unpleasantly restrictive to not allow 
> voters 
> to rank among candidates they don't
> approve.)
> 
> On the other hand the other version is simpler, and probably 
> normally 
> elects higher SU winners and resists
> burial strategy a bit better.
> 
> From your December 2 post:
> 
> > I do suggest the following: 
> >
> > In any context where being as faithful as possible to the 
> original 
> > list order is
> > considered important, perhaps because the only reason for not 
> > automatically
> > electing the top of the list is a desire to satisfy Condorcet 
> > efficiency, then
> > in this case I suggest computing both the chain climbing 
> winner and 
> > the covering
> > chain winner for the list L, and then going with which ever of 
> the two 
> > comes out
> > higher on L.
> 
> 
> Have you since retreated from this idea? Would using this on 
> the list 
> obtained from Approval-Sorted Margins lose
> (compared to just using the covering chain method) compliance 
> with 
> Independence from Pareto-Dominated Alternatives?
> 
> Could the two ever give different winners? 
> 
> Sorry to be a bit tardy in replying,
> 
> Chris Benham
> 
>