2011/7/23 Kristofer Munsterhjelm <km_el...@lavabit.com> > Jameson Quinn wrote: > >> This method leaves open the possibility for "candidate hijacking". >> Consider: Sojourner Truth has 1000 votes who vote Truth > Douglass > >> Everyone. Robert E. Lee has 1100 strategic voters who vote Truth > Lee > >> Everyone > Douglass. They dominate the honest Truth voters, so Lee is >> considered to be Truth's second choice. The Droop quota is 1900. Truth has >> no quota and is eliminated; her 2100 votes pass to Lee; and Lee is elected. >> That kind of pathology could cause a civil war. >> >> Part of this is the LNH property of STV biting us. With a system that can >> see past the top choice, you'd have 2100 votes which were essentially >> half-Douglass-half-Lee. In systems like Schulze STV, that would at least be >> helping Douglass, so the Lee voters would have to think twice about the >> tactic. And in systems like RRV, that wouldn't be any more likely to elect >> Lee than Lee's 1100 honest votes, so the tactic would be useless. >> > > Couldn't a more complex variant work in Range as well? Say you have honest > voters who prefer A > B > C, and some dishonest voters who prefer D to win. > They could either vote D first and play honestly, or they could vote A > D > > ... > > By voting A > D, their tactic is to get the second seat and also to > downweight the A > * ballot in doing so. They know that they can get D > anyway, but if they poison the A > * ballot with D, they can both have their > cake (get D) and eat it too (make the honest voters' latter choices count > less). >
I think this would not work. They'd be reducing B and C's scores on the A ballot, but they'd be increasing the overall weight of the A ballot. In RRV, this would balance out perfectly, neither helping nor harming B and C. In any system which did not use averages - anything with medians or such - the balance would not be perfect, but I suspect it would generally be good enough. JQ > If there are only two seats, this has no point. If there are many, it might > pay for a substantial fraction of the D-voters to vote A > D so as to weaken > the competitions for later seats. > > Of course, the tactical voters would have to decide whether they get most > bang for the buck by voting D, A>D, or a combination of the two. It might > turn out that the downweighting makes the strategy suboptimal in any case. > >
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