I found a practical solution to a similar problem. When I get large
gap between Rf/R in refmac I repeat the refinement in PHENIX using the
same model and the same mtz file, It has always worked for me. And I
have no theory for that observation, but the tables in publications
looked better.
Maia
Quoting "Ian Tickle" <[log in to unmask]>:
> Jackie
>
> I agree completely with Ed (for once!), not only for the reasons he
> gave, but also that it's valid to compare statistics such as
> likelihood and R factors ONLY if only the model is varied. Such a
> comparison is not valid if the data used are varied (in this case you
> are changing the data by deleting some of them).
>
> Cheers
>
> -- Ian
>
> On Tue, Oct 26, 2010 at 2:37 PM, Ed Pozharski <[log in to unmask]> wrote:
>> Jackie,
>>
>> please note that (at least imho) the desire to obtain "better" R-factors
>> does not justify excluding data from analysis. Weak reflections that
>> you suggest should be rejected contain information, and excluding them
>> will indeed artificially lower the R-factors while reducing the accuracy
>> of your model.
>>
>> Cheers,
>>
>> Ed.
>>
>> On Mon, 2010-10-25 at 17:44 -0400, Jacqueline Vitali wrote:
>>> Also if your Rmerge is high and you include all reflections in
>>> refinement, Rfree is high. In my experience, by excluding F < sigma
>>> reflections you drop Rfree a lot.
>>
>>
>>
>> --
>> "I'd jump in myself, if I weren't so good at whistling."
>> Julian, King of Lemurs
>>
>
>
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