# [EM] interpretation of the A=B incentive, 0-info Condorcet

MIKE OSSIPOFF nkklrp at hotmail.com
Sat Apr 8 16:51:35 PDT 2000

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When there's no information about other voters, and Condorcet
is used, there are 2 situations where you could improve your
outcome by voting B equal to A. They're both circular ties.
Because 0-info Condorcet has no incentive for truncation or
order-reversal, a circular tie is a natural circular tie.

In one case, it's a natural circular tie where A barely beats
B, and you & one other person could reverse that defeat by
not voting your AB preference. Maybe a B victory is worth more
to you than the ABC lottery of the circular tie solution.

In the other case, it's again a natural circular tie, but the
circular tie isn't in doubt. But B & C are near-tied for having
the lowest wv. So you can gain by helping B by not voting A over
B, if A beats B.

***

What this amounts to is that you have the option of trading
some of A's chance of winning when A has a 1st-choice majority
for an edge in natural circular ties. Of course you don't have
to, and you could vote sincerely, and if everyone does, then
if A is favorite of a majority, then A wins. But since you're
getting a little more than you're losing in the trade, there's
incentive to do it. So what's the problem? You're not ditching
your AB preference in order to get your due, as you might have
to if upranking B were the only way to elect B when B has
a clear rightful win. You've already got that, voting sincerely;
and you don't lose it even if you make the trade, voting A=B.
You're merely trading some of A's majority win for some
B circular tie win, improving your
chances in a situation where no one has a clearly rightful win.
And getting slightly the best in the bargain.

Mike Ossipoff

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