At the end of a Wed.Oct.6 message entitled "River method - updated summary" you wrote:
To do list ----------
- Do some spacial simulations - Find more criteria that distinguish between River, Ranked Pairs, and Beatpath - Test for the "Intuitive Loser Criterion", the "Sincere Expectation Criterion", and the "1st Choice Criterion"
CB: What is the definition of the "Intuitive Loser Criterion"? Is this one of your little jokes?
The "Sincere Expectation Criterion" was coined by Blake Cretney in the Margins versus Winning Votes debate,
and applies when there are as few as three candidates (when River, Ranked Pairs, Beat Path and MinMax are unanimous).
SEC is met by Margins but not Winning Votes (which is the version of River that you advocate.)
The "1st. Choice Criterion" I gather is what Mike Ossipoff used to call the Weak Favourite Betrayal Criterion, and that
was mostly an issue on the other side of the same debate.
Chris Benham
Sincere Expectation Standard Given that a voter has no knowledge about how others will vote, a sincere vote must be at least as likely as any insincere vote to give results that are in some way better in the eyes of the voter.
Or expressed as a more rigid criterion: ----- Sincere Expectation Criterion (SEC) Consider a voter with a preference order between the possible outcomes of the election. Let us call his sincere ballot, X. Now, assuming that every possible legal ballot is equally likely for every other voter, there must be some justification for the vote X over any other way to fill out the ballot, which I will call Y. This justification is given by the following comparisons:
The probability of X electing one of the voter's first choices vs. the probability of Y electing one of these choices
The probability of X electing one of the voter's first or second choices vs. the probability of Y electing one of these.
The probability of X electing one of the voter's first, second or third choices vs. the probability of Y electing one of these. ... And so on through all the voter's choices
X must either do better in one of these comparisons than Y, or equal in all. Otherwise the sincere vote can not be justified. ---- In other words, there must be some justification for voting sincerely even if the voter does not know how any one else is voting.
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