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 > > ---- Election-Methods mailing list - see http://electorama.com/em for list info
