[EM] Sparring over AV vs IRV at Least of All Evils...

David L Wetzell wetzelld at gmail.com
Fri Feb 3 06:26:19 PST 2012

On Fri, Feb 3, 2012 at 5:00 AM, Jameson Quinn <jameson.quinn at gmail.com>wrote:

> I consider the whole "encourages big parties to follow the moving center"
> thing to be so ridiculous as not to bear argument, given that, as DSH
> points out, the center is one of the worst places to be in IRV.

I said "follow" and I presume that one cannot pinpoint the center...  In my
heuristic, we get to see the numbers, but the parties don't.  They can
choose direction and to move a little or a relatively lot, but they cannot
stake any point, cuz it will change.

> Sure, it does a better job than plurality. But if you want a system which
> preserves two parties but makes them track the center, and you think that
> US exceptionalism means this is a two-party nation by nature, then you have
> a great array of systems which will accomplish your goal, and IRV is not
> one of them.

Now, who is being ridiculous?

My whole point is that it's much more important to push for the strategic
use of multi-winner elections in part of the US's system, rather than chase
our tails around trying to figure out the best single-winner election rule.
 You all cannot agree.  I think it's because in fact the diffs aren't that
great and there's no good reason that IRV can't be immunized from a
Burlington-like reversal.

> Jameson
> 2012/2/2 David L Wetzell <wetzelld at gmail.com>
>> http://www.blogger.com/comment.g?blogID=7696446405100112491&postID=7962761243854932802
>> Dale Sheldon Hess has provoked me to explain my views about IRV wrt to a
>> 1-d politics game.
>> Here's what I wrote,
>> DSH:"Place a party directly in the center. Now, if I can place two more
>> parties, I can always make your centrist lose. ALWAYS. And you can't move
>> more-centrally to do anything about it (I can actually make it so that you
>> can still win by moving AWAY from the center; how's that for perverse
>> incentives!)"
>> dlw: Ah, but in this example, the two biggest parties are in fact close
>> to the center(as I predicted)... and so the fact that the most centrist
>> party doesn't win is relatively small potatoes.
>> And as for the 3rd party candidate winning by going way from the center,
>> that's a curiosity due to the uniform dist'n of voter preferences. That
>> isn't realistic...
>> I've played with Yee's voteline thingy. The issue is with the uncertainty
>> as to what is the center, since it's something that's dynamic.
>> That's why I downplay the import of "center squeeze". The center can't be
>> cordoned off by anyone and so to pick a rule based on how it pins down the
>> center is like chasing after the wind.
>> With both IRV and FPP, there's pressure to move twds the center by the
>> biggest parties, it's stronger with IRV. Thus, the de facto center ends up
>> becoming more closely tied to the true center.
>> Let's say a shift in voter preferences has D and R at the 70 and 71 penny
>> marks and G sets up shop at 35. G wd win with both FPP and IRV, but both D
>> and R get to move again. But there are rigidities that prevent them from
>> moving too much too fast. And so the D's move to 55 and the R's to 56. And
>> then G still wins if it's FPP, but with IRV then R wins.
>> But what if D moves and R (perhaps stuck in FPP thinking) doesn't move,
>> so the positions are 35, 55 and 70? In that case, G would win.
>> Tragedy, right? But it can be expected that the next election will change
>> things further so that the G's must move to the right(or merge w. the Ds)
>> and the R must move to the L or merge with the Ds.
>> The moral of the story is that parties are like the people groping around
>> in the dark in Socrates' cave. They cannot choose exactly where on the
>> spectrum they will be. But IRV helps us to adjust and makes the outcome
>> closer to the center than o.w. with FPP.
>> If Approval Voting had been used then D would have won by moving to 64.
>> In fact all the parties wd be strongly encouraged to beeline for whatever
>> the center seemed to be and with a shifting center, they'd all stumble and
>> bump together in the dark.
>> Whereas, the Gs by taking a stand at 35 at least they succeed in moving
>> things to the left or maybe they'll get lucky...
>> It's not an exact science, which is what it should be. We want people to
>> pursue the center, but not too doggedly...
>> Sorry if that's fuzzy, but I think that's closer to real life...
>> dlw
>> ----
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