Bart: You lost me with your bullet voting example under Saari's modified Borda Count. Under Saari's modified BC method, two bullet votes for A (1,0,0) add up to (2,0,0); that is A gets a total of 2 points, while B and C get none. Can you give me a citation for Merrill's and Black's "adjusted" Borda Count method? Saari's comment about the relationship between pairwise voting and the BC, which I tried to include in my last message got cut short due to my time restrictions. Rather than trying to resend it, you may read it online in PDF format - see table 2.2 in the bottom half of page 4:
"EXPLAINING ALL THREE-ALTERNATIVE VOTING OUTCOMES," DONALD G. SAARI http://www.math.nwu.edu/~d_saari/vote/triple.pdf Steve Barney > Date: Wed, 02 Jan 2002 21:02:21 -0800 > From: Bart Ingles <[EMAIL PROTECTED]> > To: [EMAIL PROTECTED] > Subject: Re: [EM] Interesting use of Borda count > > Merrill calls this "adjusted Borda", and attributes it to Black in the > late 50's. Evidently strict ranking is required in plain Borda. In any > event, a voter can always accomplish the same thing either by voting > randomly or by cooperating with another voter. > > So in a three-candidate election with strict ranking, the point > assignments would be 2, 1, 0 (or equivalently 3, 2, 1 using the counting > method I used in my 10-candidate example). > > If the voter is indifferent between two candidates, each receives the > average of what the they would have received under strict ranking. So > if the voter bullet votes, the candidates receive 2, .5, .5 (or > equivalently 3, 1.5, 1.5). > > The first I heard of Saari's proposal was from Saari himself in an > e-mail a couple of years ago. He basically acknowledged the equivalent > as "the correct values" but went on to state his preference for 1, 0, 0. > > But Saari's method would be impossible to enforce, since the voter can > always defeat it through randomization or through cooperation. Two > voters who wish to bullet vote for A can get together and vote ABC on > one ballot and ACB on another, so that the two ballots each average 2, > .5, .5. > > Or a single voter can toss a coin to decide whether to rank ABC or ACB. > Assuming there are other voters who do likewise, these ballots should > also average out to 2, .5, .5. > > So adjusted Borda merely does what the voters could do in any event. > Although I suppose one could argue for Saari's variation as a sort of > "voter intelligence test", in that it rewards voters who are > sophisticated enough to get around the restriction. > > Bart > > > > > Steve Barney wrote: > > > > Bart: > > > > Where are these Borda rules? I know they are not in the article by Jean > Charles > > de Borda, which I referred to in my previous message. I also know that > Donald > > Saari, probably the worlds leading exponent of the BC, says otherwise. > > According to Saari it is essential to treat a bullet vote as an indication > of a > > weak preference for one candidate and indifference between all of the > unmarked > > candidates. He recommends giving 1 point to the preferred candidate, and 0 > > points to all the rest, in such a case. The essential thing is to always > give > > the same difference to each successive ranking. In _Chaotic Elections_, > Saari > > suggests that if voters are permitted to give (2,0,0) points to the 3 > > candidates by bullet voting, they will have: > > > > "an incentive to vote for only one candidate to give the candidate a boost. > A > > simple way to minimize this strategic action is to interpret the BC as > giving a > > point differential to each candidate. Thus a truncated ballot assigns only > one > > point to the candidate." > > --Donald Saari, _Chaotic Elections_, pg 151. > > > > This interpretation preserves the nature of the BC as a method based on > > pairwise compairisons. Here is excerpt (from an online article) about the > way > > in which the BC can be interpreted as based on pairwise comparisons: > > > > An important relationship (probably due to Borda and known by Nanson [17]) > > between the pairwise and the BC tallies can be described by computing how a > > voter with preferences A > B > C votes in pairwise elections. > > Thus the sum of points this voter provides a candidate over all pairwise > > elections equals what he assigns her in a BC election. This means (along > with > > neutrality 2 and the fact that each pair is tallied with the same voting > > vector) that a candidate's BC election tally is the sum of her pairwise > > tallies. (See Saari, _Basic Geometry of Voting, Springer-Verlag, 1995 > > "EXPLAINING ALL THREE-ALTERNATIVE VOTING OUTCOMES," DONALD G. SAARI > > http://www.math.nwu.edu/~d_saari/vote/triple.pdf ===== "Democracy"?: http://www1.umn.edu/irp/images/postcardAd2.jpg AR-NewsWI, a news service for Wisconsin animal advocates: http://groups.yahoo.com/group/AR-NewsWI/ __________________________________________________ Do You Yahoo!? Send your FREE holiday greetings online! http://greetings.yahoo.com