Russ Poldrack wrote:
> Dan - I agree that most fmri studies are probably underpowered, but
> I don't beleive that loosening our Type I error rate is the way to
> fix this problem. Rather, people need to run enough subjects that
> they have power to find a sufficient effect size at a reasonable
> Type I error rate.
Tom agreed, and I do too. In principle at least, I'd rather see
better-powered studies too (and I have been, it's just slow). Taking
costs into account, the two ways I can think of to do this are: (a)
more funding; and (b) fewer scientists. Neither seems like a great
idea, although it could be argued that a small number of high-quality
studies would be preferable to a large number of bad ones (given that
we could find some other kind of work for all the out-of-work
scientists).
My earlier question was meant to take the problem of underpowered
studies as a given. I was just wondering if, given that we can't
force people to run better powered studies, but we can adjust how we
review articles, maybe Type II error is more of a problem than Type I.
Or would be, if people weren't so clever about finding ways to make
Type I errors.
dan
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