On Wed, 19 Nov 2008 16:28:29 -0500 Greg <[EMAIL PROTECTED]> wrote:
> I have written up my reasons for preferring IRV over Condorcet
> methods in an essay, the current draft of which is available here:
> http://www.gregdennis.com/voting/irv_vs_condorcet.html
> I welcome any comments you have.
> Thanks, Greg
Parts of the essay are below, together with my comments, but first a
couple notes:
Bullet voting often is desired by voters when it fully expresses
their desires - sometimes there are not more than two candidates; sometimes
they have o desire to express thoughts beyond their favorite. Wanting to
do this, they may complain if required effort is more than Plurality would
demand.
Plurality is a much used election method and is fine when there are
voters wanting to express more than the bullet voting thought it permits.
Range/score requires voters to rate candidates. I like Condorcet
better, but concede this is batter than Plurality.
IRV and Condorcet use ranked ballots. These let voters rank best
liked and, behind those, others they consider worth voting for.
IRV is interested most in first rank but, when that does not
determine a winner, looks at next rank when a voter's first rank cannot win.
Condorcet looks at all that the voters say, ranking as in a tournament.
Why I Prefer IRV to Condorcet
by Greg Dennis, last edited 11/19/08
As I attempt to demonstrate below, IRV not only elects Condorcet winners
regularly in practice, but in a competitive electoral environment, IRV may
actually elect true Condorcet winners more often than Condorcet itself.
Curious, since a proper method would always elect the most qualified
candidate, assuming there is one.
Furthermore, I argue IRV is more politically feasible, prevents obscure
candidates from winning, and increases the political and technological
feasibility of proportional representation and other forms of preferential
voting, including Condorcet itself.
Conceded that IRV is more used, but not that this is deserved.
If O is truly obscure then few voters will rank O>X and neither method will
declare O as winner.
Reason #1: IRV has a track record of electing Condorcet winners
First and foremost, IRV eliminates the most common type of Condorcet failure --- the
"spoiler" scenario --- where the presence of a candidate with little core
support causes a Condorcet winner with strong core support to lose.
This makes no sense. IRV can elect those not well liked if enough of the
voters liking them rank them first.
Condorcet, looking at all that the voters say, will usually not declare B
winner if more voters rank A>B than B>A. Cycles are an exception - A>B>C>A
has too be resolved where ranking leaves a near tie among the best liked.
Admittedly, there is another situation similar to the spoiler problem --- the
"center squeeze" scenario -- in which IRV may fail to elect the Condorcet
winner.
I read this as admitting that IRV, not reading all that the voters say, can
award a nondeserving winner.
Agreed that this is probably rare, but doubt that its frequency is known
since IRV does not read all that the voters say.
Reason #2: IRV is less complicated than Condorcet
Need a closer look, considering that Condorcet offers more service.
IRV can look at how many voters ranked each candidate first and, if A has a
majority, A wins. Else need to go back to the ballots which ranked Z, the
least liked, first and count which candidate was next on those ballots - a
bit messy if the ballots are in multiple precincts.
Condorcet records all that the voters say in an NxN array. If from
multiple precincts, add the arrays together.
Can publish the arrays which show, for every pair of candidates, A&B, how
many A>B & B>A.
The occasional cycles both represent additional information - members would
each be a winner vs all outside the cycle, but need extra analysis vs each
other.
Reason #3: IRV is less susceptible to intuitive strategies
Agreed that, ASSUMING you know how everyone would vote naturally, your
friends can modify their votes to change the result.
Big problem is how you tell your friends, without others hearing and
changing their votes to compensate.
DO NOT see what could protect IRV from such strategies.
Reason #4: IRV ensures that we know where the winner stands
I do not see how this really differs from #3.
Reason #5: IRV makes Condorcet feasible
Agreed that doing IRV could make Condorcet more attractive - but, if so,
why not go directly to Condorcet?
Reason #6: IRV is the best stepping-stone to proportional representation
Current debate concentrates on single-winners such as mayors and governors.
While proportional representation could be better for legislatures,
not clear why that should affect current debate.
Reason #7: IRV has political momentum
This seems true - but not more important than looking for and trying to do
what is best.
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Dave Ketchum 108 Halstead Ave, Owego, NY 13827-1708 607-687-5026
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If you want peace, work for justice.
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