Re: [phenixbb] R/ R free (overall) and R/Rfree (for highest resolution shell)

George, what exactly you are trying to achieve by making sense of Rfree and its relation to Rwork in resolution shells? Just curious.. Pavel On 1/26/15 1:50 PM, George Devaniranjan wrote:

Thank you Tim and Pavel.

Sorry, just to follow up:

For the example I gave R /Rfree difference seems high. Can this still be down to statistical fluctuations?

I am just trying to get a feel when we can simply put it down to statistical fluctuations and when its a concern.

On Mon, Jan 26, 2015 at 4:26 PM, Tim Gruene mailto:[email protected]> wrote:

Dear George,

you may also want to take into account that the variation of Rfree is estimated as Rfree^2/k, where k is the number of reflections in the shell. If you only have e.g. 100 reflections there, this might simply a statistical fluctuation, as far as I understand.

Cheers, Tim

On 01/26/2015 10:05 PM, George Devaniranjan wrote: > Hi, > > I calculated/validated several PDB structures in Phenix.Validation (GUI) > > The R/R-free (overall) is > > 0.1271/0.1348 > > Further down I looked at the R/R-free for the highest resolution shell. > > Its 0.2538/0.2446 > > I am curious why the R-free for the *highest resolution shell* seems to be > LOWER than R (work). > > > Am I reading the information wrong? > > PDB: 3QL9 > > Thank you, > George > > > > _______________________________________________ > phenixbb mailing list > [email protected] mailto:[email protected] > http://phenix-online.org/mailman/listinfo/phenixbb >

-- Dr Tim Gruene Institut fuer anorganische Chemie Tammannstr. 4 D-37077 Goettingen

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