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On Friday 28 April 2006 08:20 am, [EMAIL PROTECTED] wrote:
>
> There are two somewhat separate questions here: (1) what data to use in
> refinement and (2) how to define a "nominal resolution" that will give the
> outside world a good idea of how far out the data extended, which needs
> some vague sort of uniform standard. I'd suggest the answers are (1) any
> datum you believe you really did measure should be thrown into the pot and
I agree.
> (2) the reported nominal resolution should be where I/sigI falls below 2,
This sounds like voodoo statistics to me. Can you suggest any mathematical
basis for choosing an I/sig(I) limit of 2 rather than some other number?
It also implies that the resolution/accuracy of the map and structural model
is entirely captured by I/sig(I) of the data, which is not true.
Consider how much cleaner maps become if you are able to do NCS averaging.
Peter Zwart already mentioned Cruickshank's empirical DPI indices
(reported by refmac, so you all can use them, right?)
These incorporate more information, and are a more direct indicator of
expected model quality. DPI does not, however, answer the question
of whether it would have been useful to process the data to higher
resolution.
Question:
I've recently seen some papers report "optical resolution".
Where does that number come from?
--
Ethan A Merritt
Biomolecular Structure Center
University of Washington, Seattle WA
