[EM] Thoughts on Burial

[Jameson Quinn]

To clarify my position:

I think that, because of social dynamics which push voter groups towards
symmetry (ie, B voters like A as much/little as A voters like B), honest
condorcet cycles will be a fraction of what they would be in "impartial
culture"-type models. Since such models usually give somewhere around 10%
cycles, or a little more, I think honest cycles will be somewhere in the low
single digits - 1%-4%. For this, I have little evidence, although it should
be noted that Romania is not at all counter-evidence; one documented
possibility in a large number of modern, polled elections is about what my
proportion would have predicted. It is certainly not evidence against "most"
cycles in a Condorcet system being due to truncation, as we have essentially
0 data on condorcet systems in public elections.

I think that the necessary conditions for truncation/burial to be a rational
strategy will be much more common. It depends a lot on the average number of
"serious" candidates per election, but assuming that with a Condorcet method
that number would be somewhere between 2.5 and 5, with a minimum of 2...
well, I don't want to pretend I've done the calculations, but my guess is
that that would lead to somewhere between 20% to 60% of elections having a
rational truncation which would affect the result. I'd imagine that a
possible truncation would actually happen somewhere from 25% to 75% of the
time. So honest cycles should be roughly 1%-4%, and truncated ones roughly
5%-45%. If these broad ranges are right, then truncated cycles will be
55%-98% of all cycles - probably 66%-90% - ie, "most".

This is why I think that system performance relating to truncation strategy
is at least as important as honest performance, at least for decent systems
where the differences between honest performance are not too large.

JQ
2010/7/14 Warren Smith <warren.wds at gmail.com>

> > I believe that Jameson Quinn is right when he says that most Condorcet
> cycles are probably artificial,
> i.e. they are caused by strategic truncation or strategic burial.
>
> --For a real life example of a Condorcet cycle in a large national
> election, see
>   http://rangevoting.org/Romania2009.html
> Contrary to Simmons' conjecture/intuition, this cycle seems to have
> been not "strategic," it was "honest" -- because the evidence for the
> cycle consists of pairwise-poll data, and there is no motivation for
> dishonesty in 2-man pairwise polls.
>
> Further, other real-world cycle examples (?) are noted, discussed 2nd
> half of section 4.
>
> --
> Warren D. Smith
> http://RangeVoting.org  <-- add your endorsement (by clicking
> "endorse" as 1st step)
> and
> math.temple.edu/~wds/homepage/works.html
> ----
> Election-Methods mailing list - see http://electorama.com/em for list info
>
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