Thanks Kristofer for the explanations. Do you know a good place that discusses the Ranked Pairs method of resolving cycles, or all the methods of resolving cycles? I would still like an example of a spoiler in Condorcet no matter how unlikely if possible. Thank you.
Kathy On Thu, Jan 21, 2010 at 2:29 AM, Kristofer Munsterhjelm <[email protected]> wrote: > robert bristow-johnson wrote: >> >> i think that the answer is "no", if a Condorcet winner exists and that all >> bets are off if a CW does not exist, except, perhaps for these >> "strategy-resistant" methods such as Markus Schulze's method. i sorta >> understand it, but since he hangs here, i think Markus should address the >> question if the Schulze method is spoiler free. > > MAM/Ranked Pairs is also pretty strategy-resistant and is easier to > understand. Schulze has the advantage of producing better results in some > cases (closer to Minmax), but if "ability to describe to the public" is > important, then Ranked Pairs wins there. > >>> Could someone please provide me with an example of the spoiler effect >>> occuring with the Condorcet method of counting rank choice ballots or tell >>> me why the spoiler effect doesn't happen with Condorcet in a few words? > > (...) > >> i would say that (with the CW existing), it's spoiler-proof. > > Yes. If there's a CW and a candidate is added, and that candidate doesn't > create a cycle, then the winner doesn't change. All the "tricky" stuff > happens when there is a cycle, or the candidate makes one. > > The advanced methods can claim further resistance: Schulze and Ranked Pairs > both make their winner decision independent of candidates not in the Smith > set. River is independent of Pareto-dominated alternatives - a candidate is > Pareto-dominated if everybody who ranks both him and some other (specific) > candidate, rank the other candidate above him (e.g. X is Pareto-dominated by > Y if all voters who rank both X and Y say Y>X, and there's at least one such > voter). > > I imagine these resistances would mostly come into play in smaller > elections. Still, they're nice to have, and their existence immediately > tells parties not to try exploiting certain weaknesses (because it won't > work). > -- Kathy Dopp Town of Colonie, NY 12304 phone 518-952-4030 cell 518-505-0220 http://utahcountvotes.org http://electionmathematics.org http://kathydopp.com/serendipity/ Realities Mar Instant Runoff Voting http://electionmathematics.org/ucvAnalysis/US/RCV-IRV/InstantRunoffVotingFlaws.pdf Voters Have Reason to Worry http://utahcountvotes.org/UT/UtahCountVotes-ThadHall-Response.pdf Checking election outcome accuracy --- Post-election audit sampling http://electionmathematics.org/em-audits/US/PEAuditSamplingMethods.pdf ---- Election-Methods mailing list - see http://electorama.com/em for list info
