Dear Rob! >From the following natural example, it seems to me DMC and wv are more truncation resistant than margins:
Sincere: 46 A>C>>B 05 C 49 B>C>>A C is Condorcet Winner. Truncation: 46 A>C>>B 05 C 49 B C still wins in DMC and wv, but B wins in margins. Furthermore, also Smith//Approval has a problem here: Although it still elects C here, only 3 of the A voters need to forget to approve of C to make B the winner: Truncation and Lazyness: 03 A>>C>B 43 A>C>>B 05 C 49 B C still wins in DMC and wv, but B wins in margins and Smith//Approval. What do you think? Yours, Jobst Rob LeGrand wrote: > Adam Tarr wrote: > >>It suggests to me that _natural_ cycles are very rare. This does >>not automatically mean that cycles can never be a problem. The >>important thing is to pick a Condorcet method where, when a >>Condorcet winner exists in sincere preference, it is extremely >>rare than any faction has a tactic where they can cause a >>favorable cycle. (I am referring, of course, to winning votes.) > > > Any such cycle-creating strategy that exists under a margins method > also exists under the equivalent winning-votes method. If the > margins strategy includes no equal ranking, the strategies are the > same. If it includes equal ranking, such as changing sincere > > 20:A>B>C>D > > ballots to > > 20:A=B>D>C > > ballots, an equally successful winning-votes strategy would be > > 10:A>B>D>C > 10:B>A>D>C > > So such situations are no rarer under winning-votes than under > margins. If anything, it seems to me that winning-votes might > provide more such opportunities to the strategic voter since equal > ranking has no effective equivalent under margins. (But it's > usually more effective just to order-reverse anyway.) It is for > this reason and the fact that winning-votes encourages equal ranks > near the top of the ballot and full ranking near the bottom even > when insincere (and even in the zero-info case!) that I prefer > margins to winning-votes. > > -- > Rob LeGrand, psephologist > [EMAIL PROTECTED] > Citizens for Approval Voting > http://www.approvalvoting.org/ > > __________________________________________________ > Do You Yahoo!? > Tired of spam? Yahoo! Mail has the best spam protection around > http://mail.yahoo.com > ---- > Election-methods mailing list - see http://electorama.com/em for list info > ---- Election-methods mailing list - see http://electorama.com/em for list info
