On Nov 24, 2009, at 12:00 AM, robert bristow-johnson wrote:
robert bristow-johnson wrote:
...
i dunno how to, other than take the raw ballot data of some
existing IRV
elections, but i would like to see how many of these municipal IRV
elections, that if the ballots were tabulated according to Condorcet
rules, that a cycle would occur.
Kristofer Munsterhjelm wrote:
...
I haven't run the data through my simulator yet, but it seems
cycles are
rare.
i have to confess that i am less worked up about what pathologies
would result from a Condorcet cycle than i am about what pathologies
result from FPTP or IRV (or Borda or whoever) failing to elect the
Condorcet winner whether such exists. we know the latter actually
happens in governmental elections. i still have my doubts to any
significant prevalence of the former.
on the rare occasion a cycle ever happens, probably Tideman Ranked-
Pairs would be the best compromise between a fairer Schulze beatpath
and some method that has sufficient "lucidity" that voters can
understand it and have confidence that no "funny business" is going
on. but whether it's beatpath or ranked-pairs or IRV rules as the
method that resolves a cycle, at least in this very rare occasion,
it's picking a non-Condorcet winner meaningfully, even if there are
conceptual ways to turn tactical with it. but then, how profitable
is it to vote tactically when there is little probability to the
conditions that would serve such tactical voting?
if it were one of those Condorcet methods and if there is little
likelihood of a cycle happening and if a savvy voter knows that, how
does it benefit his/her political interests to do anything other
than vote for their fav as their first choice and cover their ass
with a tolerable 2nd choice? how are they ever (assuming no cycle)
hurting their favorite or helping any unranked candidates (tied for
last place, in this voter's esteem) beat the 2nd choice? i really
find it hard to see the tactical interests as differing from the
sincere political interests.
Note that one very characteristic vulnerability of Condorcet methods
is burying in such a situation where a sincere Condorcet winner exists
but some voters create an artificial cycle by voting strategically.
There is one example in Wikipedia (http://en.wikipedia.org/wiki/Condorcet_method#Potential_for_tactical_voting
). (This example for some reason talks a lot about the Schulze method
although this example applies to most typical Condorcet methods.)
It is however true that in large public elections with voters that
make independent decisions and can not be fully controlled by some
central entity (like a party) or by themselves and have only
incomplete and changing poll information available this type of
vulnerability might not cause any problems. Sincere voting could thus
be the main rule in Condorcet elections despite of these
vulnerabilities.
Juho
r b-j
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