[EM] first-wave Condorcet versions for public election

[Fan de Condorcet]

James,

You wrote:

>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
>from.
>	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.
>  
>

Like many others here, I'm a big fan of Ranked Pairs (RP), Schulze, and
River.  To a great extent this is because I value approximations of IIA,
so I want a method that meets Smith-IIA and Independence of Clones.

>2. Measures of defeat strength: margins, winning votes, or something else
>(cardinal-weighted pairwise (CWP), approval-weighted pairwise (AWP), etc.)
>  
>

I recently re-read your paper on CWP.  I must confess that I didn't see
much justification for it at first, but I now find it to be well
justified and elegant.  Unfortunately, there's the matter of the
complications this will create when it comes to creating and using
ballots.  Perhaps over time I'll come to appreciate CWP more and think
it's worth the trouble, but for now I remain partial to margins.

To what I've said in regards to (1) and (2) so far I'd like to add that
for some time I've had difficulty deciding which of the aforementioned 
three methods I prefer.  Similarly I've had trouble finding any 
criterion that makes either margins or winning votes the obvious choice. 
  However, I've recently become partial to RP(m).  I'll post more about 
this in the days to come.

>3. Whether to use an anti-strategy measure (candidate withdrawal option
>(CWO), CWP, AERLO/ATLO, iterative procedure, etc.)
>  
>

I'm not about to advocate AERLO or ATLO, largely for the reasons you've 
already mentioned.  I also feel that CWO would give too much power to 
candidates.

What do I propose?  I'll briefly reiterate an idea I presented to this 
list some time ago: Make runners-up matter.  One modest example would be 
that the bylaws of an organization could state that when an officer 
becomes incapacitated, the runner-up will assume the role until 
re-election or the officer is able to serve again.  This might dissuade 
people from (some) insincere ranking and truncation.  Ranked Pairs could 
be used to find the social ranking.

(The rest of your letter follows):

>	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
>concerned.
>	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.
>
>my best,
>James
>
>----
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>  
>
Sincerely,
CF