From: hal@finney.org
Date: Wed Jul 12 2000 - 12:49:04 MDT
Eliezer wrote, quoting remote viewer Joe McMoneagle:
> > The target was later independently judged by a person who was not
> > participant to the experiment, producing a significant effect size
> > of 0.710 +/- 0.289 (p=0.007).
>
> How on Earth do they judge the significant effect size without a control
> group? Did they try having the judge check the guy's drawings against a
> randomly selected photograph as well as the target? Not as far as I can
> tell. If so, the whole experiment is entirely meaningless.
Normally these experiments involve choosing a target randomly from a
predefined set. The judges are then given the notes and drawings from
the viewer, plus all the possible targets, and judge which target most
closely matches the viewer's reports. (I suppose there is danger here
that the judges' psychic powers may be measured rather than the viewer's.)
On this basis you don't need a control, because the expectation is simply
a chance result. Standard statistical techniques will tell you if the
result is statistically significant.
I'm not sure what Moneagle means by his statistical claims above; a single
test can't produce statistical results, so presumably he is referring to
a series of tests which included the example picture. "Effect size" is a
measure beloved by experimenters who can't get statistically significant
results, but it's not clear to me what he means by giving a p=0.007 in
conjunction with effect size. Is he saying that his results were better
than chance, at the 0.7% level? That would be interesting, although of
course you'd have to look at the experimental design in detail to judge
how meaningful it is. I suspect he is making a weaker claim, though.
> And the other thing to remember is that sometimes psychic researchers,
> especially the ones writing books, will outright lie! If you read
> something and think "There's no way this could be faked," sometimes it
> just never happened.
Yes, it is always suspicious when you see results like this presented
on a web site which is selling remote viewing books and services.
It is better to stick to the academic literature.
Hal
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