Rep. Nixon rightly opined that Approval would not
be favored as a proposal because people want to be able to distinguish
their favorite from their lesser evil compromise.
Although Approval satisfies the weak Favorite Betrayal
Criterion (FBC), what people really want is the Strong FBC which allows them to
rank their Favorite strictly above Compromise, without hurting Compromise's
chances in the event that Favorite is not strong enough to win.
Some of the ranked ballot methods, including IRV
(at first blush) give the illusion of satisfying the Strong FBC, when in
reality they do not even statisfy the weak FBC that Approval
satisfies.
However, in a race that isn't too close IRV, Schulze,
DMC, and other ranked methods allow voters to get away with ranking
Favorite strictly above Compromise.
I would like to point out that although
Approval beats Shulze(wv) which beats Shulze(margins) with respect to
the weak FBC, wv is no better than margins when it comes to the Strong FBC
that everybody covets so strongly.
How does DMC fit in here? I believe that, like
wv, it is better than margins, when it comes to the weak FBC, and on a par with
winning votes. I believe DMC slightly beats wv when is comes to
the Strong FBC, because (among other reasons) in at least
some cases where ranking Compromise equal with Favorite is
required in wv methods, under DMC it suffices to approve Compromise without
ranking it equal to Favorite.
In a recent posting I have detailed the precise
conditions for a violation of the Strong FBC in DMC, and have explained
why they are very unlikely to be met in practice. It would be helpful
if someone could do a similar analysis for Shulze(wv).
[I'm assuming that most people will not consider equal
approval as a violation of Strong FBC as long as they can still distinguish by
rank.]
A simple method that completely satisfies the weak
FBC, and comes close to satisfying the Strong FBC is Majority Choice Approval
(MCA). Voters specify a favorite as well as other acceptable
candidates. If no candidate is listed as favorite on more than fifty
percent of the ballots, then the most acceptable candidate is
elected.
That said, an even simpler method comes closer to
satisfying the Strong FBC than any of these other more complicated
methods: Asset Voting:
Voters vote for their favorite, who represents them by
proxy in an election completion convention. Write-ins are
allowed. In the completion convention the proxies (i.e. the candidates
including write-ins) get as many votes (their "assets") as they were granted by
the voters. In other words, whatever ballots they cast in the election
completion method (some reliable method like Approval, DMC, or Shulze) are
given weights equal to their "assets."
This method is called asset voting because if
these proxies diappoint their supporters, then after
the election they will be kicked out into the street and be
left sitting on their assets.
I think that we should go for Asset Voting,
MCA, or DMC. If we are going to get more complicated than DMC, we
should go for Approval Weighted Pairwise, which is Schulze with defeat strength
measured by Approval Opposition, which is a great improvement (with respect to
Strong FBC) over wv at negligible cost.
Forest
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