Here is my analysis of the following profile, up to this point: > > 1 ABC > > 1 ACB > > 1 CAB > > 1 CBA > > 1 BCA > > 1 BAC
All methods agree on a complete tie for this profile, of course. If one of the voters reverses her top 2 candidates (for example, A>B>C switches to B>A>C), she is either rewarded, punished or neither, by the following methods as indicated: Plurality: R Borda Count: R IRV: N Pairvote: N Copeland: R If she rotates her sincere second choice up to first, moves the sincere last choice up to second, and puts her sincere first choice last (for example, A>B>C rotates to B>C>A), she gets the following rewards, etc: Plurality: R Borda Count: N IRV: N Pairvote: N Copeland: N When I say she is "rewarded," I mean that her second choice is elected. When I say she is "punished," I mean that her last choice is elected. When I say she is "neither" punished nor rewarded, I mean that neither her first nor second choice is elected, due to either a tie for first place or an otherwise indeterminate outcome. Therefore, as you can see, according to my analysis thus far, these methods rank as follows from most to least manipulable: Plurality: RR Borda Count: RN Copeland: RN IRV: NN Pairvote: NN OR Plurality > Borda~Copeland > IRV~Pairvote Can anybody go further with this analysis? SB PS: While I'm at it, let me make a correction to my previous message. The 2nd sentence of the following paragraph, change the word "sincerely" to "insincerely," so as to read: "If too many people insincerely put Nader between Bush and Gore, and voted either Bush>Nader>Gore or Gore>Nader>Bush, Nader would have been elected." > barnes99 said: > > The Borda Count will punish an insincere vote in some cases, and that is > > actually an incentive to vote sincerely. If too many people sincerely > > put Nader between Bush and Gore, and voted either Bush>Nader>Gore or > > Gore>Nader>Bush, Nader would have been elected. Therefore, you need > > some information to successfully manipulate the BC, Steve Barney Richard M. Hare, 1919 - 2002, In Memoriam: <http://www.petersingerlinks.com/hare.htm>. Did you know there is an web site where, if you click on a button, the advertisers there will donate 2 1/2 cups of food to feed hungry people in places where there is a lot of starvation? See: <http://www.thehungersite.com>. ---- For more information about this list (subscribe, unsubscribe, FAQ, etc), please see http://www.eskimo.com/~robla/em
