[EM] TACC (total approval chain climbing) example

[Forest Simmons]

Michael,

I agree with your assessment of the current possibilities, and I realize
that Woodall and Benham have the advantage of being based on a familiar
runoff idea.  It is also possible to do chain climbing on the IRV
elimination order, but monotonicity and immunity to second place complaints
would be sacrificed.

Immunity to second place complaints says that if you re-run the election
with the (old) winner removed, the new winner will be someone beaten
pairwise by the old winner.  Neither Benham nor Woodall satisfies this nice
property. In other words if X is the Woodall Winner (say) there might be
another candidate Y that (1) becomes the Woodall winner when X is removed,
and (2) is not beaten by X pairwise   This may seem fishy to the Y
supporters.

Steve Eppley's concern about all of the truncations being used up by one
very bad candidate should not be a concern if the voters realize that no
totally truncated candidate can win no matter how many additional
truncations there are among the remaining candidates.  A Pareto Dominated
candidate is covered by each of  its dominating candidates, but the TACC
winner cannot be a covered candidate.

Another way to address Eppley's concern: Instead of the implicit approval
order for TACC we could (without sacrifice of any nice property) use the
Bucklin Order according to the equal ranking (whole) version of Bucklin.
This order is determined primarily by the median rank of the candidate and
secondarily by how much support it has at that rank or above.

You probably already knew all of this, but I wanted to get it into the
archives for the record.

By the way, what happened to the regular election methods archives?

Forest



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