[Election-Methods] RELEASE: Instant Runoff Voting

[Dave Ketchum]

Aaron's words make sense, but perhaps I can do better talking about 
two methods that, while using the same ballots but going at the task 
in different ways, usually agree as to winner.

IRV looks only at best liked, discards candidate with fewest such 
votes, and repeats until a winner remains.

Condorcet looks at ALL the ballot rankings, discards candidate liked 
less when compared with each other candidate, and repeats until no 
such candidates remain.

Since IRV only looks at momentarily best liked, it can discard 
candidates Condorcet would see many voters truly liking better.

Condorcet can complete this part with three or more candidates 
remaining because they are in near ties such as A>B and B>C and C>A. 
This is called a cycle and requires special analysis to decide which 
member should win.
      Note that cycles require a mixture of voters with differing 
goals - no one voter can vote all the inequalities described above.

DWK

On Mon, 28 Jul 2008 17:10:49 -0700 (PDT) Aaron Armitage wrote:
> --- On Mon, 7/28/08, James Gilmour <jgilmour at globalnet.co.uk> wrote:
> 
> 
>>That all ranked ballot voting systems must be assessed
>>using criteria and tests that can be applied to them all,
>>is your view, and
>>it may be the view of others.  But I would suggest it
>>ignores some fundamental differences between the voting
>>systems.  IRV in
>>particular makes no pretence at complying with a range of
>>social choice criteria  -  it is a complete different kind
>>of voting
>>system.
> 
> 
> I find this a really astonishing thing to say. IRV and all other ranked
> choice systems ask for the same input from voters and produce the same kind
> of output, namely a single winner. For you to say they differ so
> fundamentally that no common standard can be appealed to looks an awful lot
> like special pleading. And how can you argue that we should adopt IRV
> instead of Condorcet or Borda or Bucklin if you have to common standard
> from which to argue that IRV is better? Or is it only the criteria that
> put IRV in a bad light that are irrelevant?
-- 
  davek at clarityconnect.com    people.clarityconnect.com/webpages3/davek
  Dave Ketchum   108 Halstead Ave, Owego, NY  13827-1708   607-687-5026
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