[EM] possible improved IRV method

Allen Pulsifer pulsifer3-nospam at comcast.net
Thu Jun 29 17:12:14 PDT 2006


Hi Rob,

> > 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".
> 
> Sure there is, and it's no more arbitrary than IRV's way.

I can't agree with this, because I think there is a practical difference
between identifying a majority consisting of voters who have strong support
for the winner vs. identifying a majority with weak support for the winner.
IRV will always do the former, while Condorcet will not.

Going back to the example I gave, the Condorcet majority that elected D was
made up of everyone who did not rank A the highest, i.e., the Not A's, and
they all coalesced around D.  In reality a coalition like that would never
happen and if it did, it could not be held together.  In fact, in the
example I gave, the only thing that allowed D in the party was the A voters:

166:A>B>D>C
166:A>C>D>B
 83:A>D>B>C
 83:A>D>C>B
  etc.

If only a small portion of those voters realized that their strongest
head-to-head competitor was Candidate D, and then proceeded to downgrade him
to last place, then under any system D would be shut out and A would win.
That is what would happen in reality, and IMHO, in order to have healthy
governance, that is what should happen.

> I think 
> many real- world voters would order-reverse under Cordorcet 
> just like they would under Borda (though many others would 
> vote sincerely under any method). These days I see Approval 
> and Range Voting as much better reforms.

I agree, just like the example above.

I noticed while researching voting systems that 7 states used Bucklin Voting
aka the Bucklin System aka the Grand Junction System back in the early
1900's (source: Wikipedia).  Apparently, one of the problems with this
system was that choices made at lower rankings could help defeat your
favored candidate.  As a result, many voters started entering only their top
choice and it degenerated into plurality voting.

IMO, every voting system should have the property that choices you make at
lower ranks do not help defeat a candidate you prefer.  Otherwise, there is
a strong incentive to truncate your ballot or downgrade strong competitors
(see also The DH3 Pathology, http://rangevoting.org/DH3.html)

I also note that according to Wikipedia, in a few states the Bucklin System
was found to violate the constitution.  Does anyone know where there is more
info on this?  Has anyone taken a look at proposed voting systems to see if
they might also have constitutional issues?

> These days I see Approval and Range Voting as much better reforms.

Approval voting does not enamor me.  My alma mater uses it to elect
trustees, and it doesn't work because people want to express a preference,
not just approval, and if they try to do that with approval voting, their
vote ends up getting split, just like plurality voting.  The result is that
the extreme conservative alumni group has been able to get their nominees
elected even though they make up only 20% of the voters.

I haven't studied Range Voting in detailed, but it seems rather complicated.
Can we expect the voters to know enough about the candidates and have the
patience to assign 0-10 ranks to approx. 5 to 25 candidates?

> There has been some research into this issue both on this 
> list and in academia.  Check out Lorrie Cranor's dissertation 
> work on Declared- Strategy Voting at 
> http://lorrie.cranor.org/dsv.html .  My current doctoral work 
> is related to hers.

Thanks.  I will check these out.

Allen




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