[EM] strategy-free Condorcet method after all!

[Kristofer Munsterhjelm]

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.

That's what the data might provide information about. If it is 
representative and cycles are rare, then there's little to worry about, 
except how opponents might exaggerate the faults. If cycles are common, 
then one should be careful to pick the right cycle-breaker.

> 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. 

Yes. I think so, too, but Schulze has momentum (within technical 
organizations, mostly), so the question is which is greater an advantage.

> 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?

There would be two kinds, I think: attempted "vote management" by 
parties and what we might call "ignorant strategy" that the voters do by 
themselves, and which only distorts the outcome if lots of people do it. 
The latter is not much of a threat, I think, and the method only has to 
weather the former for a few elections before the parties see it isn't 
going to work.
In small committees, the two would converge: poison pill type tricks are 
possible with Condorcet methods, as well, but that's not the application 
we're speaking of at the moment.

> 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.

Ignorant strategy could take the form of "I really really hate [major 
party X], so I'll put him last", where there are also worse candidates 
in the running, but the voter is used to two-party systems. Burial by 
accident, as it were. Warren claims that will destroy most Condorcet 
methods, because DH3 applies to that instance as well, but I'm not so 
sure. It *does* destroy Borda, but so does agenda manipulating (fielding 
loads of clones).