# [EM] IRV vs Plurality

Kristofer Munsterhjelm km-elmet at broadpark.no
Sun Jan 17 01:50:55 PST 2010

```robert bristow-johnson wrote:

> we can continue on like this with more discrete levels and all we'll get
> are gradations of the above.  it's all a matter of degree.
>
> but the 2-position slider is a 1-bit piece of information: "No","Yes",
> that's the minimum a voter has to judge.  that's qualitatively
> different.  here's why:  with the multi-level (3 or more), then order
> has to be considered with candidates that you approve or disapprove.
>
> but the multi-level or continuous slider (3+) requires *more* than just
> ordering information (who is preferred to whom?), it requires *spacing*
> information.  like "i hate candidate D worse than i hate C whom i
> dislike more than B whom i like less than A."  you have to decide that D
> is twice as badder than C than C is badder than B or some other value
> judgement.  what if you just don't feel like making such a precise
> judgement?  then you get your dartboard.

To me, it seems that the method becomes Approval-like when (number of
graduations) is less than (number of candidates). When that is the case,
you *have* to rate some candidates equal, unless you opt not to rate
them at all.

That won't make much of a difference when the number of candidates is
huge (100 or so), but then, rating 100 candidates would be a pain. I'd
say it would be better to just have plain yes/no Approval for a "first
round", then pick the 5-10 most approved for a second round (using
Range, Condorcet, whatever). Or use minmax approval or PAV or somesuch,
as long as it homes in on the likely winners of a full vote.

I guess that if you (hypothetically speaking) like Range, you could
argue that while there's a "dartboard" effect, the noise is unbiased and
so will cancel itself out given enough voters: the voters may not hit
exactly at the satisfaction point, but close enough.

```