preliminary criteria reply

[Mike Ositoff]

David--

When I was replying to some of the criteria you named, I
left out the tacatical ones. More about the rest of them
in my next posting, but right now I just want to emphasize
that the one that says that no one should have incentive
to not rank his favorite in 1st place is unquestionably the
thing that I consider most important for a voting system.

In general, no one should have to rank a less-liked alternative
equal to or (especially) over a more-liked one. But when someone
has incentive to not rank their favorite 1st, that's surely the
worst violation of all.

***

It seems to me that the criterion about tyrants is the Majority
Loser Criterion. And that the one about split-vote is really
equivalent to the Independence From Clones Criterion. 
Maybe IRO meets that criterion, but Schulze's method meets it
too, along with additional especially important criteria--
such as the tactical criterion mentioned above.  

***

It seems to me that all the VA methods meet that "1st Choice
Criterion" (that says no one should have to not rank his favorite
1st). One thing for sure is that no one has to do that to
protect a CW. But I don't believe there's any incentive to do
so, even offensively.

Approval, though it doesn't let you vote your favorite over
everyone, when you need to support a compromise, it does let
you give a full vote to your favorite--as much of a 1st place
vote as anyone can give to any candidate.

But Approval probably doesn't meet your 1st Choice Criterion
as it was intended, since Approval doesn't let you vote
your favorite _over_ everyone. That's why I say that Approval
gives half the strategy benefit of the best rank methods.

More later
Mike Ossipoff