[EM] What is the ideal election method for sincere voters?
Abd ul-Rahman Lomax
abd at lomaxdesign.com
Wed Mar 7 22:56:16 PST 2007
At 08:03 PM 3/7/2007, Scott Ritchie wrote:
>On Wed, 2007-03-07 at 13:41 -0500, Abd ul-Rahman Lomax wrote:
> > If we consider the underlying preferences and ratings to be
> > expressable in Range, then we can consider that the sincere voter
> > sets -- or can be seen as setting -- an Approval cutoff rating, and
> > all candidates rated above that level are approved and all below it
> > are not. Essentially, the voter has divided the candidates into two
> > sets, and the vote is sincere if every candidate in the approved set
> > is preferred to every candidate in the disapproved set.
> > There is no known good reason for voting insincerely under Approval.
> > It is never forced.
>This definition bothers me a bit.
I can sympathize.
> We tend to think of "sincere" votes
>as non-strategic, but the method you just described for "voting
>sincerely" can involve a whole lot of strategy based around resizing the
>sets and setting the approval threshold.
If the underlying ratings are accurate, in my view, a sincere voter
does not become insincere through the setting of an approval cutoff
at any level. While this could be called "strategic," and it
certainly would change with knowledge of the general condition of
society, it could only be "insincere" in a technical sense that
assumes insincerity if a vote is altered based on what the voter
thinks might fly.
Placing the Approval cutoff is a *judgement* that the voter makes.
The *sincere* judgement would be based on "Given what I know about
possibilities, what am I willing to accept."
If we ask the raw question of the voter, if wishes could be horses,
what would you accept or "approve," a voter might simply select the
favorite and any candidate absolutely equal to this. But that is not
what we are seeking. We are seeking, in Approval, for the voter to
set a "compromise" cutoff.
It is as if there were two elections: in one voters sincerely rate
candidates. There still is a similar problem, but the essence of
sincere rating is that the numbers reflect the preference strengths
of the voter, not some judgement of what will succeed. If you think
that Joe will make a fabulous President, the best possible, in
sincere ratings you would have Joe at the top. If you think that
someone else would be excellent, but not as good as Joe, then you
would rate this other person highly, but lower than Joe. You would
not take into consideration that lowering that rating could cause the
second person to lose to a less desired candidate. Rather, you would
simply rate candidates according to your estimation of their value in
the office. If you prefer one candidate to another, but the
preference is very slight, less than the resolution of the Range
election, you might rate them identically, it would not be insincere.
Then there is the second election: what is the Approval cutoff? In
this election I must consider what I think attainable. The fact is
that I'd make a better choice in this regard if I have the results of
the Range election first. Setting the Approval cutoff is a more
difficult decision to make "accurately" than rating the candidates, I
expect. But most voters simply won't make it that complicated. As
I've frequently mentioned, I'd expect, unless the candidate field
broadens significantly over present practice, most voters will simply
vote for their favorite, which will be one of two frontrunners. A few
voters will have a favorite who is not a frontrunner, and these will,
as suggested, vote for their favorite and the frontrunner they
prefer. And maybe for more than that, depends.
But if there are more than two frontrunners, more than two in reach
of winning the election, it could get quite complicated....
So, the good news is that coming up with a set of sincere ratings
should not be terribly difficult (as long as we don't insist that
they be nailed down precisely). I'd probably start with a ranking,
because pairwise comparison is easier. I doubt that I'd get caught in
a Condorcet cycle!
Then I would set my least favorite at zero and my favorite at max and
then work in between. Theoretically, I don't have to use the
extremes, but if I consider that my vote should count equally with
others, I would.
But to vote Approval requires an additional, substantially more
complicated step if I want to do it precisely with a large number of
candidates. I must set the approval cutoff. This is not dependent
solely upon candidate preferences and ratings. Rather, it is
dependent upon what compromises I'm willing to accept. If I approve a
candidate who I'm actually not willing to accept, I'd leave the
country if he wins, I'd call that insincere. And if I disapprove of a
candidate whom I'd actually be pleased to have win, I'd similarly
call that insincere. But there is a lot of room between these two rocks.
I don't see any forced insincerity in Approval. It might look like
that because of confusion between the two separate decisions.
One test would be, if A is presented for ratification of his
election, would I vote for or against A? I'd call a "fully" sincere
Approval vote a vote on this question. And, in fact, Approval has
been described that way.
But that is fairly demanding of compromise, because the pain of the
election failing might be worse than the pain of an even fairly bad
winner. This is equivalent to having NOTA on the ballot, and
approving of any candidate one would prefer to NOTA. Libertarians
might have a very simple ballot to fill out!
>We're not doing that though. We're both acting very strategically here
>based on information about other voters to influence the election
>outcome, and at least one of us is changing our vote as a result. That
>fits just about any reasonable definition of "strategic voting" yet
>you're calling us both sincere.
Some reserve "strategic voting" for voting where one reverses
preferences to gain strategic effect. We could call that "fully insincere."
Approval never requires full insincerity, nor does Range. I gave a
definition above for full sincerity in Approval. Full sincerity in
Range isn't so difficult.
In Range and Approval, full sincerity may be strategically
suboptimal, that is, the voter may be able to improve expected
outcome by, for example, not Approving of a candidate that the voter
would actually accept.
In an election between Bush Sr. and Clinton, I would, in fact, accept
either. But this does not mean that I would vote for Bush Sr. I
didn't, and not just because voting for both would have invalidated my ballot.
The fact is that the real election was between the two. With two
candidates, Approval cutoff is pretty easy to set! You just approve
your favorite. Because if you really didn't care, you could
accomplish the same "not care" effect by not voting at all.
Rather, remember, the goal of voting is to use aggregated preference
to select the ideal winner. So if I have a preference, I should
express it. Does this mean that the method should allow me to express
Not necessarily. Election methods are an attempt to compress
deliberative process into a single poll. Approval compresses the
process in a certain way, as I've noted, it asks two questions, the
answer to the first being concealed and not directly expressed, it is
only input to the second question.
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