[EM] IRV vs Condorcet

[Dave Ketchum]

I responded to an email; got a complaint that I misspoke,

Misspoke?  I thought I was moderator?  I am - of NY; email was on NYS.

At least some should see what I write here about IRV vs Condorcet.   
Both use ranked ballots, with almost identical rules for voters  
(Condorcet permits equal ranking).

IRV voters can express their desires, but vote counters are not  
required (in fact not even permitted) to count all that they have  
voted.  Steps:
1. Stack ballots per top rank vote.  If one stack has a majority of  
the stacked ballots, this is winner.
2. For each ballot in smallest stack, remove one or more names to get  
to a stack to move it to.
3. Ballots that have no stack to move to are done.
4. Back to step 1 with remaining ballots.

Problems:
      Only the top rank candidate on each ballot is seen at any time -  
lower ranks do not get considered until becoming top rank.
      Once a candidate has been smallest stack, or never had a stack,  
any votes seen for that candidate get ignored.
      Backers make a big deal of "majority" - but it is of the final  
stacks, not of all ballots.
      Suppose Tom, Dick, and Harry share all the top rank votes, and  
Joe gets all the 2nd rank.  Then if raced in pairs Joe would get twice  
the votes of each of them - but Joe is invisible in IRV.

Condorcet counting can read the same ballots as voted for IRV.  Here  
counting is for each candidate ranked on a ballot.  Except for  
candidates ranked as high or higher by this voter, this candidate gets  
counted as winning against all others.
      Usually the counts will show one winning against every other  
one.  When a few win over the remainder, but not over each other  
(e.g., A>B>C>A), resolution is doable but takes more effort among the  
few.

About some groups:

InstantRunoffNY · Multi-partisan group to discuss IRV and other  
election reform--what we can do in New York  start 2000/12 -  
effectively died in 2002 due to excessive spam.

InstantRunoffNYS · Instant runoff voting in New York State  start  
2002/04 because of above spam - active thru 2006

instantrunoff-freewheeling · An unmoderated list about Instant Runoff  
Voting, an alternative electoral system.  start 2000/11. active thru  
2006

IRV4NY  failed attempt to replace above.

Condorcet-subscribe at yahoogroups.com  2005/08
      Seems we do not have many such groups, and this one is not very  
active.

Election-Methods mailing list - see http://electorama.com/em for list  
info
      Condorcet gets some discussion here.

Dave Ketchum