To Blake, re: strategy

[MIKE OSSIPOFF]

Blake said:

Some countries use plurality with successive elimination for things like
leadership conventions. I think Americans use it for speaker of the
house. Since the strategy is very similar, I think that awareness of
strategy in one would be good evidence of awareness of strategy in the
other.

I reply:

Sure, but there are also countries that use IRV, and that's obviously
the best evidence about IRV in action.

I'd said:

>
>information from (2 by e-mail, one in person), none of whom know
>eachother, told me that it's common for preferrers of small parties
>to insincerely vote one of the big-2 parties' candidates in 1st place
>, to avoid "wasting their vote". One of those Australian voters with
>whom I spoke had just voted in that way in the most recent election.
>But they all said that such voting is common in Australian IRV
elections.

Blake replied:

I don't consider those people a representative sample.

I reply:

Fine. Do a proper scientific statistical study. In the meantime,
the evidence that I've described is all that's been offered from
Australia. Rob has quoted some results from Ireland that confirm
IRV's spoiler problem, a problem closely associated with LO2E.

I might also add that when IRV was adopted in Australia it was hoped
that it would encourage parties to run more than 1 candidate per
party. For the most part that hasn't happened.

Blake continues:

As well, their
strategy does not appear to be rational.

I reply:

Excuse me for repeating this, but you may have missed it before:

Say there are 3 candidates, Favorite, Middle, & Worst.

Say Middle is closer to Worst than to Favorite. Hardly an implausible
assumption, since it's unlikely that Middle is exactly in the middle.

Say that Favorite isn't expected to have a 1st choice majority. Not
implausible either, since, if the candidates are roughly equal in
1st choice support, none has more than about 33% of the total
1st choice support.

Now, if Favorite is your favorite, should you sincerely rank Favorite
in 1st place? Why? Favorite can't win, based on our assumptions.
If you rank Middle in 1st place, at least you might save Middle from
immediate elimination, avoiding an avoidable Worst victory.

Not only is insincerely ranking Middle in 1st place a rational
strategy, but it's the only rational strategy for someone who
prefers Favorite>Middle>Worst.


Blake continues:

But until I
see some media coverage, I'm going to suspect that this is just a few
election method enthusiasts.

I reply:

Three Australians who independly report the same thing about
Australian voting by preferrers of 3rd parties.

Blake quoted me:

>
>I've made the effort to get some information about IRV strategy in
>Australia. I realize that it's easier for you to question that than
>to get information yourself.

Blake replied:

Why should it be up to me to find evidence for a phenomenon that I do
not believe exists?

I reply:

You say it doesn't, those 3 Austalians say it does. I politely suggest
that they're in a better position to know about that than you are.

All I'm saying is that the evidence that we (including you) have
been able to obtain so far all points to a lesser-of-2-evils
favorite-dumping strategy in public politcal IRV elections.

If you require a scientifically-conducted statistical survey, I'm
not saying that you should have to conduct one if you don't want to.
It would be difficult for anyone not residing in Australia anyway.

But what we have is the plausible scenarios in which voters will
have incentive to use favorite-burying strategy in IRV, and the
evidence from those Australians whom I've had the opportunity to
ask. They say that strategy is common in Australia.

You haven't given any argument why IRV shouldn't cause favorite-
burying strategy, and you haven't given any evidence that such
strategy isn't in use in IRV elections. The existing argument &
evidence says that the problem can be expected to exist, and that
it in fact does exist.

I'd said:

>As I presumed, your Strong FBC is more important to you, which
>makes you dissatisfied with FBC.

Blake replies:

It's quite possible to want to avoid having people vote candidates equal
to their favourites without advocating Strong FBC. Just as it is
possible to want to reduce crime without believing in some unmeetable
zero-crime criterion.

I reply:

Ok, so you're just saying that it's good to be able to guarantee
that _sometimes_ voters won't regret that they didn't insincerely
rank someone equal to their favorite, and that they sometimes won't
regret that they didn't insincerely rank someone over their favorite.

Sorry, but guarantees that contain the word "sometimes" or "maybe"
don't sound very reassuring.

I think what you're getting at is that, while Approval never gives
any incentive to vote someone over your favorite, it routinely gives
strategic need to rank someone equal to your favorite. In comparions,
methods like IRV & Ranked-Pairs(margins) sometimes _do_ give strategic
need to vote someone over your favorite, but at least they
sometimes don't give strategic need to vote someone equal to or
over your favorite. And you consider that an advantage for IRV &
Ranked-Pairs(margins) over Approval. Is that it?

For you, "sometimes" is good enough a guarantee. You have a gambling
nature.

One problem, of course, is that one can't always know just when
Ranked-Pairs(margins) or IRV will make them sorry that they didn't
bury their favorite.

Blake continues:

[regarding insincere equal-voting]

I don't think ordinary voters have much of an opinion on it, because
they've never heard of approval. When they do get involved, they seem
to be drawn to IRV far more than approval, based on the strength of the
movements.

I reply:

Here there's lots of money paying for IRV promotion. And the IRVies
are promising people that IRV will end the lesser-of-2-evils problem.
So of course that sounds good to people. People are misled to believe
that IRV won't give incentive to rank insincerely.

I'd said:

>Yes, because the IRVies don't understand that IRV will often give
>voters a strategic need to vote someone over their favorite.

So they would suddenly stop disliking voting someone equal to their
favourite if they knew that IRV will sometimes give someone an advantage
by voting someone over their favourite.

I reply:

Some people who have listened to CVD, and been convinced by them,
have rejected IRV when they found out that they'd beend deceived.

But I don't guarantee that everyone who prefers IRV would do so,
because some people adopt a proposal to commit to, and then won't
consider any evidence on the issue.

Blake continues:

Note that I don't say strategic
"need" because that's just a loaded word. Any time anyone has a chance
at strategy, you could call it a need for strategy. It's really only a
need if they need the candidate to win.

I reply:

I suppose one could call anything whatever they wanted. However
I've told you what I mean by defensive strategic need, as oppposed
to strategic incentive:

Defensive strategic need means that
insincere voting is needed in order to enforce majority rule or
protect the win of a sincere CW.

For example, with Ranked-Pairs(margins) there is defensive
strategic need to bury one's favorite. You objected that, with
the wv Condorcet versions, voters could sometimes gain by insincere
equal ranking. But those opportunities are limited to certain
natural circular ties. Criteria met by the wv versions tell their
amount of freedom from defensive strategic need.

The wv versions are liked because they
are intended to minimize defensive strategic need, and they do
a good job of it.

With Ranked-Pairs(margins), and with Approval, there's defensive
strategic need to insincerely equal-rank. RP(m) will less often
make you regret that you didn't equal rank, but it's only a matter
of degree. But RP(m) sometimes makes you regret that you didn't
bury your favorite, and that can never happen with Approval.

Blake continues:

>Once again, I never mentioned strong FBC. But as for your question, I
think that a criterion should be judged by what passing it implies. We
know (or suspect) that a method that passes FBC will be at least as bad
as approval on the equal-voting issue, unless it is one of the peculiar
strategy-free methods.

I reply:

You're just saying that one must choose between different
desired properties. The fact that different desiderata are
incompatible doesn't discredit either. It just means that one must
choose.

You like the gamble of maybe not regretting that you didn't
insincerely equal-rank, or bury your favorite, and sometimes
regretting that you didn't bury your favorite. Approvalists prefer
the absolute guarantee of never having any incentive to bury one's
favorite, in comparison to your guarantee that you sometimes won't
regret that you didn't equal-rank or bury your favorite.

You suggest that most people tend naturally to like your gamble
too. We don't know that, since most IRV-convinced people have only
heard from the IRVies. If you're right, then we must offer a rank
method. If so, then we can offer them a better one than RP(m). But
many prefer the advantages of Approval. And Approval is so much
easier to implement, and is so much less of a radical change from
FPTP, that Approval is likely to be more winnable than a rank method.
The rank methods are completely new voting systems, were they to
replace FPTP. Approval isn't a completely new voting system, just
an obvious improvement, a big voter-freedom improvement, on the
old Plurality. Unlike RP(m), also, Approval doesn't add new disadvantages, 
like failure of Participation, Consistency, IIAC,
Heritage, & Regularity.

Blake continues:

In the same way, a method that passes IIAC will
either not accept full rankings, or discard most of them. So, even
though IIAC may sound good, I think that it is actually bad for a method
to pass it, since it implies other things that are not good.

I reply:

That's a bizarre thing to say. What you mean is that, while
passing IIAC is a good thing, you feel that methods that don't
pass it have other advantages that you consider more important.

Methods that don't pass IIAC might pass CC, SFC, GSFC,
&/or SDSC. But IIAC is compatible with FBC & SARC, as are Participation, 
Consistency, Heritage & Regularity.

Every choice between desired properties could be called a
"mixed blessing". So we pick the properties that are more important
to us. You prefer the gamble that sometimes has you sorry that
you didn't bury your favorite, because it sometimes doesn't
make you regret not equal ranking.

Mike Ossipoff








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