[EM] first-wave Condorcet versions for public election
jarmyta at antioch-college.edu
Sun Mar 13 03:48:33 PST 2005
Dear election methods fans,
In a recent message, I noted that there is no broad consensus among
Condorcet supporters as to which completion methods would be most
appropriate for a few key scenarios. I don't really expect to establish
such a consensus, but I would at least like to address some of the issues
involved, and hear where some of the other Condorcet supporters are coming
There are at least three areas of possible divergence:
1. The base method: Minimax (candidate whose worst loss is least bad),
sequential dropping (drop the weakest defeat that's in a cycle until a
candidate is unbeaten) ranked pairs, river, beatpath, Condorcet completed
by another method, approval hybrids, etc.
2. Measures of defeat strength: margins, winning votes, or something else
(cardinal-weighted pairwise (CWP), approval-weighted pairwise (AWP), etc.)
3. Whether to use an anti-strategy measure (candidate withdrawal option
(CWO), CWP, AERLO/ATLO, iterative procedure, etc.)
Area (1) is not necessarily the most contentious; i.e. most people who
like beatpath like ranked pairs just about as much, and so on. However, I
would not feel especially good about a method that isn't Smith-efficient,
even to start out with. So that cuts out plain minimax as far as I'm
I prefer winning votes for area (2), entirely for anti-strategic reasons.
This starts to bring us toward area (3), i.e. strategy. I agree that
winning votes has a better protection against the burying strategy than
margins, but I still suspect it to be somewhat unstable in certain
situations. If I am correct (which is debatable, of course), this brings
us into slightly uncomfortable terrain. CWO is the simplest anti-strategy
method, but some voters might be intuitively uncomfortable with the idea.
CWP has an intuitive interface, but one which requires very sophisticated
ballots, and the tally rule is complex. AWP, AERLO/ATLO, and similar
methods have a somewhat confusing interface, and while the tally rules are
not terribly complex, they are not brilliantly easy to explain, either.
I know that Mike Ossipoff has said that we should all come together
around a winning votes method without an additional anti-strategy measure.
But I'd like to hear what some other people think.
I'm not even sure what I would recommend, if I was in a position to
recommend something for public elections. I lean towards starting out with
a winning votes version of sequential dropping (or any one of ranked
pairs, beatpath, river, if there isn't an intense need for simplicity)
with a CWO. But that's subject to change, with further discussion.
More information about the Election-Methods