For myself, I decide on the high resolution cutoff by looking at the
Rsym vs resolution curve. The curve rises, and for all data sets I have
processed (so far) there is a break in the curve and the curve shoots
up. To near vertical. This "inflexion point" is where I decide to place
the high resolution cutoff, I never look at the I/sigma(I) values nor at
the Rsym in the high resolution shell.
As a reviewer, when I have to evaluate a manuscript where very high Rsym
values are quoted, I have no way of knowing how the high resolution
cutoff was set. So I simply suggest to the authors to double check this
cutoff, in order to ensure that the high resolution limit really
corresponds to high resolution data and not to noise. But I certainly do
not make statements such as this one.
I have seen cases where, using this "rule" to decide on the high
resolution limit, the Rsym in the high resolution bin is well below 50%
and cases where it is much higher. Like 65%, 70% (0.65, 0.7 if you
prefer). So, in my opinion, there is no "fixed rule" as to what the
acceptable Rsym value in the highest resolution shell should be.
Fred.
Van Den Berg, Bert wrote:
There seem to be quite a few “rule” followers out there regarding
resolution cutoffs. One that I have encountered several times is
reviewers objecting to high Rsym values (say 60-80% in the last
shell), which may be even worse than using some fixed value of I/sigI.
On 3/3/11 9:55 AM, "Ed Pozharski" <epozh...@umaryland.edu> wrote:
On Thu, 2011-03-03 at 12:29 +0100, Roberto Battistutta wrote:
> Does anyone know the origin or the theoretical basis of this
"I/sigmaI
> >3.0" rule for an appropriate resolution?
There is none. Did editor ask you to follow this "suggestion"? I
wonder if there is anyone among the subscribers of this bb who would
come forward and support this "I/sigmaI >3.0" claim.
What was your I/sigma, by the way? I almost always collect data to
I/sigma=1, which has the downside of generating somewhat higher
R-values. Shall I, according to this reviewer, retract/amend every
single one of them? What a mess.
Cheers,
Ed.
--
"I'd jump in myself, if I weren't so good at whistling."
Julian, King of Lemurs
