On Jan 10, 2010, at 1:21 AM, Jameson Quinn wrote:
2010/1/8 Kevin Venzke <[email protected]>
Hi Dave,
--- En date de : Ven 8.1.10, Dave Ketchum <[email protected]>
a écrit :
> I said "approval", not
> "Approval". I read Range ratings of A-1, B-9, and C-2
> as saying B is much more strongly approved than A or B.
You are looking at the meaning of Range ratings on a ballot, but you
don't seem to care how Range uses this information. That's what I'm
talking about.
Kevin Venzke
If I understand you correctly, I think that this is an important
point, and should be expressed more clearly. It is, in my opinion,
one of the ONLY valid arguments against Range, and yet it is (again,
my opinion only) in some cases a telling one.
The point is that Range encourages naive voters to vote non-
strategically. If even sophisticated people like Ketchum's can laud
range ballots' expressivity, without noting that strategy could
limit this expressivity, we can imagine voters, often far less
sophisticated, will fail to understand range strategy at all. Some
voters will, strategically, vote approval-style, and other voters
will NOT.
A range proponent might argue that this just means that Range will,
in practice, perform somewhere between the (excellent) theoretical
Range result and the (pretty good) theoretical Approval result.
Indeed, simulations show that, for any randomly distributed constant
proportion of strategic voters, Range performs well, and in fact
outperforms most other methods (including Condorcet methods) given
the same proportion of strategic voters. However, this argument
assumes random distribution. Such an assumption is not only
unjustified in the typical election; in fact, there are grounds for
assuming the contrary. Voting groups are, by definition,
ideologically distinct, and thus there is every possibility for
their propensity for strategic voting to be distinct. If groups do
thus vote strategically at different rates, Range can give seriously
deficient results - with sufficient strategy gap, even the worst
candidate can win. (Condorcet methods, on the other hand, will tend
to still elect the Condorcet winner despite any strategy, unless
results are close and/or some voters use a specifically misguided
strategy).
Yes. Another way to describe this situation is to say that strategic
voting pays off. A voter/party that uses strategy is more likely to
win than one that votes sincerely. For many that is a good enough
reason to vote strategically. And when many do, also the hesitant ones
may follow.
I think it would behoove Range advocates to think about these
issues, because one horror story of this kind could be more
obviously unfair than many of the worst pathologies of other systems.
However, there are forms of Range voting which would avoid this
problem. Most obviously, there is Approval itself, which is
technically a form of Range. That can be extended to any version of
Range which disallows or strongly discourages most "weak" votes. For
instance, there could be options to vote only 0 ("worst"), 1("bad"),
50 ("intriguing"), 99 ("better"), and 100 ("best"). 50 is labeled as
"intriguing" because the option is intended particularly for little-
known candidates whom a voter believes, but is not sure, deserve
support, not for well-known candidates who are simply of average
quality. This would give additional expressiveness beyond Approval,
without a significant risk of pathological situations where a
strategic minority imposed their will over an unstrategic majority.
For instance: in a standard "two frontrunner" scenario, where no
voter was uninformed about either of the frontrunners and so nobody
rated either as merely "intriguing", such a system could not give
the "wrong" strategic-plurality winner unless the gap were less than
1% (ie, closer than 49.5%-50.5% of the two-way vote).
In practice it might however make sense to rate the two frontrunners
strictly at 0 and 100. Elections are often tight and therefore also
smaller differences than 49.5%-50.5% may be crucial / quite often
decide which one of the frontrunners will win. This approach would
mean that all other ratings (1, 50, 99 and others) would be reserved
for giving sincere opinions on candidates that can not win.
(There could be also strategic thoughts on what will happen in the
next elections to these candidates and their parties. This kind of
future related considerations could lead to using only values 0 and
100 also for all those candidates whose support level one wants to
influence (although they can not win this time).)
Juho
Jameson Quinn
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