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

Jameson Quinn jameson.quinn at gmail.com
Fri Feb 3 06:38:41 PST 2012

2012/2/3 David L Wetzell <wetzelld at gmail.com>

> 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.
Enough words.

If you propose a model that is well-specified enough to be tested in
silicio, we'll talk. Certainly, nothing you've said so far is unreasonable
for that; a one-dimensional spectrum with an unknown shift between
elections, voters with some bias towards the top two parties from the last
election, and parties with some cost for mobility, especially with an
inability to switch positions, trying to maximize their win percentage with
the least movement. I believe that in such a model, IRV would be closer to
Plurality (ie, bad) than it would be to any other good system (approval
with reasonable voter strategy, Condorcet, MJ, Range, or SODA). I hope we
could make some kind of a bet, and that my expected winnings plus my
curiosity would be enough to make it worth my while to actually do the test.

Otherwise, I'm tired of debating this back and forth. I'm an empiricist,
not a platonist. (Middlebrow?)

> 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?

See above.


> 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.
>  dlw
>> 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
>>> ----
>>> Election-Methods mailing list - see http://electorama.com/em for list
>>> info
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.electorama.com/pipermail/election-methods-electorama.com/attachments/20120203/8d89d3e6/attachment-0004.htm>

More information about the Election-Methods mailing list