[EM] The worst about each system; Approval Preferential

[Jameson Quinn]

2010/5/27 Abd ul-Rahman Lomax <abd at lomaxdesign.com>

> At 12:31 AM 5/27/2010, Jameson Quinn wrote:
>
>> As Abd already said, you can avoid the runoff if only one candidate has a
>> majority. Abd's Bucklin proposal tricks many voters into extending more
>> approvals to decrease the chances of a runoff.
>>
>
I should have been more precise. I believe that with Bucklin/Runoff, people
will honestly rank more candidates than are approved with approval/runoff.
This will help avoid some unnecessary runoffs, which is a good thing. It
will also possibly improve the utility of the result for society. However,
it is a strategic mistake on their part. Thus, I call it a "trick"; if they
fully understood the situation, they probably would just vote strategically.
Being a trick doesn't make it evil; on the contrary, if anything, it helps
the social utility. But it does make it unstable; people might see through
it, and it would stop working. (If they have a rational degree of doubt in
their own judgement of which option is best, and are voting altruistically,
and believe that a majority of voters are voting altruistically or have no
negative-sum interests at stake, then it's not a mistake, but the first part
at least clearly doesn't describe most.)

In APV, adding additional preferences (beyond the approval ballot) is not a
strategic mistake, which I think makes it more robust. It also still has the
same justifications in human psychology.

Correct strategy in APV when the two frontrunners are ideologically distinct
is to disapprove one and everybody worse, prefer the other and everybody
better, and approve everybody in between. If they're near-clones
ideologically (ie, near to same value for most people who aren't strong
supporters of one of them), then do the same using the third frontrunner and
the most-distinct of the first two; that automatically means at least one
approval, for the other clonelike frontrunner. Both of these strategies, if
widely followed and if the "frontrunner" determination is common knowledge,
never lead to a runoff.

> Bucklin, very similar to what I'm proposing, was widely used for a time. We
> know that some voters don't like being restricted to three ranks in RCV.
> Additional expression, *if voluntary*, is, in my book, a good thing.
>

If voluntary and honest. But one dishonest strategic expression can "poison"
a number of honest expressions. Moreover, even semi-honest strategy creates
two classes of voting power - strategic and nonstrategic - which hurts
legitimacy.

That's why adding levers and knobs to your voting system is dangerous if
they can be used strategically with impunity. I believe that the best
solution to expressiveness is not a "kitchen sink" system such as some of
Abd's proposals, but a drastically simple system with an official,
nonbinding, Range/Condorcet/Bucklin poll attached.


>> Voters rank each candidate as preferred, approved, or unapproved.
>>
>
> So you have an explicit disapproved rank? How is this treated compared to a
> blank?


Same as blank. Exists only to prevent accidentally approving when trying to
vote "against". Tallied together but break-out percentages reported for
anyone who cares.


>
>
>   If any candidates have a majority ranking them at-least-approved, then
>> the one of those which is most preferred wins outright.
>>
>
> Right. With quite possibly bizarre outcomes.


No more bizarre than closed primaries, at the very worst. That is, a solid
majority coalition might elect its more radical member, not the centrist.
"Solid majority" means that the median voter is a member of that coalition,
supporting the "radical" on that side over all other candidates. Unlike
closed primaries, if there's a majority but it's not solid, the centrist
from that side is probably elected.

Personally, I don't see that as necessarily bad - think of it as a small
taste of time-series proportional representation. In other words, a bit of
diversity, instead of centrists winning always, could be healthy.


> ... instead of his 1, 0.75, and 0, it should be 1, 0.5, 0. But that isn't
> used in this present statement of the method. It's simply Range analysis.
>

This is only for the nonbinding poll. People can set these numbers
explicitly, those were just defaults. Actually, the right default value for
the "approved" rank is the average of the value people explicitly write in
for that rank. I do suspect that people would be more likely to write in
values above 0.5 than below it, so I suspect that number will be closer to
0.75 than to 0.5.


>
>
>   If not, then the two candidates which are most preferred against all
>> others (ie, the two Condorcet winners based on these simple ballots, or the
>> two most-preferred in case of a Condorcet tie) proceed to a runoff
>>
>
> Utility theory would not suggest his pair. Utility theory suggests the sum
> of scores candidates. I only suggest including a Condorcet winner because of
> conflict between utility theory and democratic majority theory. If a result
> is to be based on "greater summed good," the majority should accept it.
>

Utility theory only works for a nonbinding poll. If you're relying on it
working, people will manipulate it, and that manipulation will be arguably
biased; that is, one side will arguably be doing it more than the other.
(Whether there truly is a bias or not doesn't matter; the mere appearance of
bias undermines legitimacy.)



> [...]
> I didn't see this note until the end, here:
>
>
>  **Insofar as voters agree with the statement "I trust society to get the
>> right answer, even if it's not the one I agree with", it's not a trick. Most
>> people don't seem to believe that, though.
>>
>
> It's not a trick in any case. It's quite open and clear. Do you want to see
> a decision made now, or do you prefer it to be deferred? This is the choice
> faced by voters in repeated ballot, it's perfectly ordinary. Do they want to
> complete the election, or do they want to keep voting until the cows come
> home? It creates a certain natural force toward compromise, not enough to
> cause people to abandon what is important to them, but to relax their
> standards *a little.* Bucklin naturally does this within a single ballot, so
> rerunning a Bucklin election extends it a bit more, with an opportunity for
> the voter to revise the voting robot instructions that a Bucklin ballot
> represents.
>

OK, this is fair. It's not a trick. But it is unstrategic honesty on the
voters' part, and thus less robust than strategic honesty.

I'll stop repeating myself now.

JQ

>
>
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