--- Dave Ketchum <[EMAIL PROTECTED]> a �crit :
(3) Strategy concerns, not necessarily catastrophic but enough to complicate voting. For example, under Condorcet voters have the ability to dump a low-utility Condorcet winner using a prisoner's dilemma-based strategy. Some of us are quick to discount the possibility of voters using this type of strategy, but this phenomenon is actually quite common. Civil society is built on individuals sacrificing to varying degrees for the common good. We willingly forgo certain things without expecting immediate compensation, because we expect to be compensated in the "big picture". Otherwise we'd all be out looting museums. Or common courtesy-- take the simple act of holding a door open for a stranger carrying an armload of packages-- it's not like you expect a tip. Rather, you expect to reap the benefits of living in a society where people hold doors open for strangers with packages.
Please explain "prisoner's dilemma". I do not remember any suggestion of such.
http://groups.yahoo.com/group/election-methods-list/message/11387
Thank you - I had read it, and not that long ago.
"Some of us are quick to discount..." probably refers in part to me.
If people do altruistically truncate, it means that Condorcet is probably less likely to elect a low-utility candidate than if otherwise. But I think Bart's point is that voters shouldn't have to think about this.
My reaction is that this supposed regard for others is best ignored. Starting with what Bart wrote May 27:
Not entirely true, although this involves a prisoner's dilemma.
If, in advance of the election, the vote count is not known, but A and C are believed equally likely to win in a head-to-head contest, the A and C factions can agree to truncate and block B from winning, thereby giving A and C each a 50% chance of winning. This increases the expected utility of the outcome for both A and C, if B was a likely winner on fully-ranked ballots.
Some believe a prisoner's dilemma strategy to be unworkable, since either side can "cheat" the other by failing to truncate, but the cost of being cheated seems low in this case. If nothing else, it seems like a bit of a dilemma to decide how to play the prisoner's dilemma.
Bart is saying: Starting with: 49 ABC, 2 BAC, and 47 CBA (estimating a near tie). A and C backers could agree to lock out B by truncating to A and C. Then each worries about whether they can expect the other to truncate.
In this case I like better acting on regard for SELF:
Starting with: 49 ABC, 2 BAC, and 47 CBA
Translation: A and C backers each PREFER B over their major enemy.
A and C backers hear something UGLY about B
Selfish response is: 49 ACB, 2 BAC, and 47 CAB
No value in a fragile agreement. Or, if B remains attractive to some As and/or Cs, why would they join the proposed agreement - or honor it even if they agreed ahead of time?
Seems to me the words about expected utility are misleading. A and C backers obviously rank their preference first. They properly go next for whichever remaining candidate is their preference among such.
Also seems to me that "low-utility candidate" gets misused:
ABC says that this voter assigns most utility to A and something less - perhaps negative - to C. Voter has placed B between - PERHAPS almost as positive as A; PERHAPS almost as negative as C.
Looking at the initial estimates above, A and C could perhaps be rated as low-utility with some voters rating A or C as high-utility and others giving each the opposite rating. B could possibly be rated as moderate-utility, for noone has assigned B last choice.
Kevin Venzke [EMAIL PROTECTED]
-- [EMAIL PROTECTED] http://www.clarityconnect.com/webpages3/davek Dave Ketchum 108 Halstead Ave, Owego, NY 13827-1708 607-687-5026 Do to no one what you would not want done to you. If you want peace, work for justice.
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