At 05:26 PM 1/8/2009, Juho Laatu wrote:
This is a reply to an old mail. (I didn't cover this well enough earlier)
--- On Fri, 5/12/08, Abd ul-Rahman Lomax <[email protected]> wrote:
> > One
> > could say that any placement of the approval
> > cutoff is sincere as long as it respects the
> > sincere preference order of the voter. But one
> > could also require that the approval cutoff should
> > be placed on some "main gap".
>
> Why? I don't see any reason why that particular
> position is better than any other. It is simply *easier*.
If one's ratings are A9 B3 C2 then the
"big gap" is between A and B, and it is
very natural to the voter to approve
only A. Doing something else might be a
result of strategic thoughts.
The whole concept of strategic voting is flawed when applied to
Range. Voters place vote strength where they think it will do the
most good -- if they think. Some don't. Approval is essentially, as
Brams claimed, "strategy-free," in the old meaning, and the only way
that it was at all possible to call it vulnerable was that critics
claimed that there was some absolute "approval" relation between a
voter and a candidate.
Consider the example given; on some absolute scale, let's assume, we
have A9 B3 C2. It seems to make sense that a sincere vote would be to
bullet vote for A. But what if A is essentially an irrelevant
candidate, the voter knows that A cannot win? Great candidate, far
better than the frontrunners B and C. Given that B and C are, in the
estimation of the voter, the only realistic candidates, then, the
voter votes for both A and B. "Sincerely?"
What does sincerity have to do with it? It's a *choice,* a *vote*. We
choose things based on our expectations, which include probabilities.
On the other hand, suppose that the ratings are A9 B8, C2. If all
three candidates are viable, in the estimation of the voter, then
voting for A and B makes sense, because the loss of utility from B
winning is small compared to the loss if C wins. But if C is not a
viable candidate, a looney, perhaps, the voter is confident that the
vote for C won't even make 1%, *C is irrelevant.* What we really have
is a two-candidate election between A and B, and the voter votes
sincerely for the favorite.
It's claimed by some that Approval doesn't meet IIA. It does if the
voters treat irrelevant alternatives as such! And if they don't, they
aren't irrelevant in the ordinary meaning.
> There is no absolute approval cutoff
In other words, it's not possible to define an Approval vote as
"sincere" or "insincere," unless it reverses preference, which is
insincere, and which Approval does not reward; at best it is moot.
There are no "absolute" and measurable
opinions. Much depends on what the voters
think they are supposed to do.
An odd view, in my opinion. What the voters are "supposed to do"? Who
is the sovereign who sets these requirements?
Here is what I'm supposed to do, as a voter: exercise my choice.
Hopefully, it's an informed one, which includes understanding the
voting system and how it works, the context, and the likely
consequences of my action.
How I vote is *entirely* up to me. It's secret ballot, we can
presume. I can take a pen and scribble on the ballot. I can vote for
every candidate or none. I can vote for one or many. I can write what
I like on the ballot, and nobody can do anything to me, there is no
law against silly votes or nasty votes or, especially, selfish votes.
I can vote in a manner that I think will overall benefit society, or
I can vote in a manner that will benefit me personally, hang the rest of it.
What happens to the ballot depends on the rules, but those rules do
not constrain me, unless I want my vote to be effective, in which
case I need to know them. I can use them as I choose.
In Open Voting, i.e., Approval, I can vote independently for or
against each candidate, there is no connecting constraint. (Perhaps I
vote for the candidate by marking a box on the ballot for that
candidate, I vote against the candidate by default.) Essentially, I
am putting a weight in the box of no candidates, one candidate, or
more than one. The candidate with the most weight wins. It is an
action, and the consequences of the action do not have any connection
with my intention: if I have a "sincere" intention, or a "strategic"
intention, it doesn't matter.
The big objection that someone like Saari makes to Approval is that
it's indeterminate: you cannot just take a preference ranking of the
candidates and predict, simply from that, how voters will vote. But
we can, nevertheless, make some predictions, and Saari totally missed
this, he imagines that voters will vote according to an insane "mean
utility" strategy, which, of course, is highly vulnerable to clones
and irrelevant alternatives. Now, if the "mean utility" is adjusted
by probabilities, that's another story. But that's not what Saari did.
What voters will really do, in substantial numbers, is bullet vote.
They will pick their favorite and leave it at that. And, in fact, in
most elections, this works just fine! There are exceptions, and those
who would need to add additional approvals generally know who they
are. It gets difficult only in quite rare circumstances.
It's unpredictable. Quite like intelligence in marginal circumstances.
They may
think that they should mark all candidates
that they accept for the position, or they
may be just told that they should mark
candidates that they want to promote in
the given competitive situation (based on
the available poll information, expected
winning probabilities etc.).
We tend to overemphasize "poll information." Every voter is a sample
of the population, and the voter generally knows where this sample fits.
What's been really interesting in studying nonpartisan elections with
IRV is how the supporters of candidate A appear to be, with respect
to their preferences for B and C, quite like the overall population.
If the overall population prefers B to C, A supporters will, with
similar percentages, prefer B to C. I must say that this was totally
unexpected; but the key is "nonpartisan." When partisan loyalties and
prejudices are involved, it is quite different.
The Burlington election, in spite of having party affiliations on the
ballot, was pretty much like this. I haven't looked at the lower
choices of the Democrat and the Progressive, but the voters for the
Republican candidate, in spite of the relative political positions of
the parties, were about evenly split between the Democrat and the
Progressive, with a slight majority of them voting for the
Progressive candidate, i.e., more to the left. The Democrat was
considered "Republican light" by the Progressives. She had been a
Republican, previously. She was, in the legislature, a moderate
Democrat, according to one source.
Burlington is not a very large town; it's even a bit surprising that
the mayoral election there is partisan, many towns that size don't
have party affiliations on the ballot.
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