[EM] strategy-free Condorcet method after all!

[Dave Ketchum]

FPTP:  For most elections this can handle the decision needed - though  
get near a tie and suspicion pushes toward doing a runoff.

IRV:  Does let voters do ranked voting, but we find plenty of reasons  
to complain about how it counts the votes.

Condorcet:  Lets voters do ranked voting for more than one, indicating  
which they like best.
      Matters often to let them express their desires more completely  
when they wish - though they can often adequately express their  
desires via bullet voting.
      Matters MUCH, though rarely, to sort out more complex  
decisions.  It is for this ability that we need such as Condorcet.

It is for the last topic, where there may be a cycle and no CW, that  
analyzing votes is more of a challenge.

The Llull method will find the CW if it exists.  Else it will find a  
cycle member.  Deciding which takes a bit more looking at the N*N  
array.  We debate how to choose a winner, which I claim should only  
consider cycle members (any cycle member would become CW if other  
members were rejected).

Tactical voting?  PROVIDED you know how all others will vote, you may  
be able to influence results by responding based on what you know.   
That results can be affected via such makes sense.  That you can both  
have the needed information and modify your vote as you plan is a  
suspect dream - perhaps someone can do useful analysis as to frequency  
of attainable useful results for such.

Dave Ketchum

On Nov 23, 2009, at 5:00 PM, 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.
>
> r b-j