[EM]

[MIKE OSSIPOFF]

You probably know this already, but it's often said that, if
the important output is an ordering of the candidates, then Tideman's
method is best. If considerations about the output ranking are
more important than SSD's or BeatpathWinner's advantages.

A brief wording of Tideman:

Drop the strongest defeat that's the weakest defeat in a cycle.
Repeat till there are no cycles. At that time, any candidate with
no undropped defeats wins.

[end of definition]

I've heard that Tideman can become a bit awkward when pairwise ties
& equal defeats are likely, which is how it is when there aren't
lots of voters.

The idea is to create a transitive output ordering by dropping defeats,
only dropping a defeat it it's the weakest defeat in a cycle, and
minimizing both the number and magnitude of defeats dropped.

Those are the goals that lead to Tideman's method.

The preferred version of Tideman's method on this list is the
version that measures the strength of a defeat by the support of
that defeat--the number of people voting for that pairwise defeat.
Defeat-support, as opposed to margins (defeat support minus defeat
opposition). Tideman himself used margins. Defeat-support gives us
compliance with important strategy criteria.

I believe that, when considerations related to an output ordering
aren't the most important, BeatpathWinner, and its equivalent,
Cloneproof SSD, and SSD, are more preferred on this list. Of course
that's something that we could establish with a poll, if we
choose voting systems for the demonstration poll, or for a later
demonstration poll. I personally prefer SSD to Tideman. Cloneproof
SSD when there aren't many voters and pairwise ties are possible.

Mike Ossipoff

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