[EM] Issues, Condorcet, and IRV (was: IRV vs. plurality)

[James Green-Armytage]

"Eric Gorr" <eric at ericgorr.net> writes:
>Let's say, we have something like:
>
>03 AB
>01 C
>
>Now, either A or B is going to win.
>
>However, there is one last ballot to count. The person casting this 
>ballot would greatly prefer that A wins, but sets the cutoff to 
>include B.
>
>A & B still tie.
>
>Tie is resolved in B's favor.
>
>That voter ended up with a worse result from their point of view by 
>participating and setting the cutoff in the wrong place.

Eric, I don't understand. If the person doesn't vote, then there is a tie
between A and B. If the person does vote, there is still a tie between A
and B. I don't understand how the person's vote made the result any worse
from their point of view.

Here is a definition of the participation criterion (from Markus, I think)
that I dredged up from an earlier posting:

"The participation criterion says that the participation in the election
by a same-voting group of voters should never worsen (due to the opinion
of this group) the result of the elections" 

So, if you *delete* the ballots cast by those voters altogether, it
changes the outcome to something they prefer. This is the test of the
participation criterion; if this can happen given rational votes, then the
method fails the criterion.

The criterion does not deal with this: If you *change* the ballots cast by
those voters, it changes the outcome to something they prefer. This is not
a statement of the participation criterion; it is another issue altogether.

James