[EM] The responsiveness of Condorcet / Monotonicity

Alex Small asmall at physics.ucsb.edu
Mon Jul 14 16:07:02 PDT 2003

> The only situations when PR is not appropriate is when PR is not
> possible. In  those instances ( for a single position) we are left with
> trying to use the  least bad single seat method.

Here you say (and I agree) that proportionality is not a concern when
discussing offices that, by their nature, should be single-winner (e.g.
executive offices).

> Monotonicity is undoubtedly a desirable feature of an electoral method.
> I do  however feel that no method can be perfect and that other features
> are more  important ( proportional representation of parties,
> proportional representation  of opinion, maximum freedom of  voter
> choice regarding the individuals who  represent you, etc).

Here you say that proportionality considerations are more important than
monotonicity.  That may be a valid statement in regard to STV and other
non-monotonic PR methods, but IRV is a single-seat method.  Single-winner
methods cannot be proportional, so proportionality isn't even on the table
as an issue when we're discussing IRV.  So you can't just dismiss concerns
over monotonicity by saying "proportionality is more important" if we're
talking about using IRV for _executive_ offices.

Now, you might dismiss concerns over monotonicity by arguing that the
problem occurs only rarely, or by arguing that IRV's handling of first
choices is a virtue that outweighs monotonicity concerns.  We could debate
those questions.

However, here's a thought about IRV and proportionality anyway:  In the
US, it is likely that IRV will be implemented as a reform long before PR. 
IRV might result in more third-party candidates getting 10% or more of the
first-place vote in legislative races, a lot better than the 0.5%-5% that
a lot of third-party candidates get right now in American plurality
elections.  Even if third parties don't win many legislative races, people
will probably take notice of this, and it might get people thinking about
the need for PR.

Going a step further, a situation where Condorcet gives a party 70% of the
seats for 20% of the first-place votes might cause even more people to
contemplate the need for PR.

So although the ideal situation is obviously to start electing legislators
via PR, single-winner reform might spark more people to at least
contemplate PR by making third parties more visible.  Remember, when there
are only 2 parties, and the majority party draws the districts, the
defects of single-member legislative districts are less obvious to the
casual observer, because the majority party got a majority of the seats.

Just a little silver lining there...


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