[EM] possible improved IRV method

Allen Pulsifer pulsifer3-nospam at comcast.net
Wed Jun 28 19:00:15 PDT 2006

Hello Dave,

There are a few things I like about IRV as opposed to Condorcet.

First, I think IRV is a reasonably straight-forward extension of current
runoff methods.  I think it will be more readily understood and accepted.
In contrast, Condorcet could be described as "wonkish".

Second, IRV satisfies the "Majority Rules" criteria.  In the Majority Rules
criteria, at the end of the election, you can point to the group of voters
who form a majority and were responsible for the election of the winner.
This serves three important purposes.  First, it lends legitimacy to the
outcome.  Second, it tells everyone who the governing coalition is.  Third,
it provides feedback to the candidates that is critical for making them
responsive to the voters.

The final effect is not to be underestimated.  The candidates are not fixed
constellations in the sky that we choose between.  Instead, they constantly
fine-tune their positions, attempting to maintain the backing of a majority.
This fine-tuning is a good thing -- it is what ensures our elected officials
represent us.

Our two party system however does have issues.  It has evolved into a
polarized equilibrium, where the Republicans and Democrats have drawn a line
that divides the electorate down the middle.  Worse, with the primary
system, the nominees themselves are at the middle of their respective
parties, which is about the 25% percentile point relative to the electorate
as a whole.  The only centrists tend to be "Blue" candidates from "Red"
states, and "Red" candidates from "Blue" states.  One of the goals of
alternative voting system is to provide a viable way for voters to pick from
the middle rather than the extremes.

Getting back to Condorcet, there is a majority in each pair-wise comparison,
but for each pair, it is a different set of voters.  There is no way, at the
end of the election, to go back and say "This is the majority that elected
the winner".

In certain cases, Condorcet can also result in a strange outcomes.  Take for
example, the following (admittedly contrived) situation:


The total votes is 999.  Candidate A, with 499 top rankings, is only 1 vote
shy of a majority.  His two second rankings would bring him across the
threshold.  Nonetheless, Candidate D, with 2 first preferences and 498
second preferences is the Condorcet winner.  Doesn't that seem backwards?

Note I believe I may have been incorrect about my previous proposal meeting
the Condorcet criteria.  While under that proposal a candidate can only be
eliminated if he loses a pair-wise comparison, the comparisons happen after
candidates have been eliminated and votes redistributed.  This would seem to
have some sort of effect, but I'm still hashing it over.

In addition, the ideal voting system to be monotonic.  Classic IRV is
recognized as not monotonic.  One of the goals of my proposal was to at
least find a monotonic method.  I don't know if it accomplishes this of not.
This may be a problem inherent in IRV: whenever you eliminate a candidate
and then retabulate votes, it introduces the potential for non-linearities.

With respect to "strategic voting", I believe the ideal voting system would
be essentially immune from strategic voting.  Each voter would state their
sincere preferences, and the tabulation would be responsible for determining
the winner as if each voter had executed their optimal strategy.

Finally, your comment regarding tabulation and precinct voting is a point
well-taken.  I have another idea for a possibly improved IRV that I will
post separately.

Best Regards,

Allen Pulsifer

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