Dear Manfred,

I completely agree. However this is not routinely reported.

The discussion is of removing one indicator of this signal, rather than 
replacing it with a superior measure - the latter is something I would more 
actively support however would involve adding new stuff which is an uphill 
battle.

All the best Graeme
________________________________
From: Manfred S. Weiss <manfred.we...@helmholtz-berlin.de>
Sent: 10 June 2021 13:43
To: Winter, Graeme (DLSLtd,RAL,LSCI) <graeme.win...@diamond.ac.uk>; 
CCP4BB@JISCMAIL.AC.UK <CCP4BB@JISCMAIL.AC.UK>
Subject: Re: [ccp4bb] Should Rmerge be reported?

Dear Graeme,

a better number to look at is Isa. Instead of low resolution Rmerge.
Seriously. We monitor that to assess beamline performance.

Cheers, Manfred

Am 10.06.2021 um 14:42 schrieb Winter, Graeme (DLSLtd,RAL,LSCI):
Once again I find myself jumping to the defence of this rather poor statistic!

Yes, Rmerge is a very poor estimator of "data quality" and has many well 
published flaws related to multiplicity, but the low resolution Rmerge, if 
combined with a multiplicity > (say) 5, is a good indicator of whether the data 
set is "good" or there is something odd going on.

For example, if you claim a 1.6A structure with an inner shell Rmerge of 0.11, 
5-fold multiplicity and an overall I/sig(I) of 68 I would "smell a rat"

To me it does have a value, as an unbiased estimator of your true unmerged 
I/sigma as it does not depend on any manipulation you have done to your sigmas. 
It is not a good estimator of where the resolution should be cut or any other 
decisions.

The above situation could be an indicator that there was radiation damage, for 
example

There are better ways of measuring damage - Rd, Rcp, ... but these are not 
commonplace graphs as I understand it. This little number in the middle of the 
table does give you that hint.

So while I would say rejecting a paper because it was not included was very 
heavy handed, I would not like to see it erased from all papers either.

All the best Graeme
________________________________
From: CCP4 bulletin board <CCP4BB@JISCMAIL.AC.UK><mailto:CCP4BB@JISCMAIL.AC.UK> 
on behalf of Manfred S. Weiss 
<manfred.we...@helmholtz-berlin.de><mailto:manfred.we...@helmholtz-berlin.de>
Sent: 10 June 2021 13:30
To: CCP4BB@JISCMAIL.AC.UK<mailto:CCP4BB@JISCMAIL.AC.UK> 
<CCP4BB@JISCMAIL.AC.UK><mailto:CCP4BB@JISCMAIL.AC.UK>
Subject: Re: [ccp4bb] Should Rmerge be reported?

Dear Cristy,

this is really hilarious. And it just shows how attached
some ppl are to outdated numbers. Against better
knowledge.

It has been shown many times that Rmerge is flawed
at various levels.

The only reason I can see to report it is to be backwards
compatible. But of course, this is a really weak reason.

I would love to see it disappear.

All the best
Manfred

Am 10.06.2021 um 14:25 schrieb Maria Cristina Nonato:
Dear Colleagues
Hope to find you all well and healthy.

I have a question regarding Rmerge. In recent years, we have published our 
crystallographic structures in highly respected journals using CC1/2, 
I/sigma(I), completeness and multiplicity as quality parameters for our 
diffraction data.

Recently this year, We submitted a paper using the same strategy, but one of 
the reviewers asked us to provide the Rmerge, arguing that providing this data 
was compulsory and it was important to estimate radiation damage.

We replied to the editor arguing that Rmerge should not be used as a quality 
parameter, as suggested by more recent literature, such as the article 
published by Karplus and Diederichs (10.1016/j.sbi.2015.07.003). We also argued 
that there are modern and efficient methods to estimate radiation damage ( 
doi.org/10.1107/S1600576718005241<http://doi.org/10.1107/S1600576718005241>; 
doi.org/10.1107/S0907444909040177<http://doi.org/10.1107/S0907444909040177>). 
It is my opinion that an experienced crystallographer can even  monitor 
radiation damage over the course of data processing.

And our paper was rejected !!!!!!!!!!!!!!!! due to the fact I did not provide 
Rmerge which I certainly could have done If I found necessary.

Journals like Nature ((https://www.nature.com › documents › 
nr-tables-xray<https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&ved=2ahUKEwiigtb19uHwAhWS3YUKHSB1AdkQFjABegQIAxAD&url=https%3A%2F%2Fwww.nature.com%2Fdocuments%2Fnr-tables-xray.doc&usg=AOvVaw1RbfYvNeiEM07FBEOohMig>)
 and even IUCr Journals 
(https://journals.iucr.org/f/services/structuralcommunications/) still list 
Rmerge as a data to be reported. I always took this as a suggestion since there 
are people still using Rmerge for data cutoff, but I never took this as if 
Rmerge was a compulsory data to be reported.

I would like to hear the opinion of this community. Should we compulsorily 
report Rmerge?  If so, Why?

Cheers,

Cristy
--
Cristina Nonato
Associate Professor
Laboratório de Cristalografia de Proteínas
Faculdade de Ciências Farmacêuticas de Ribeirão Preto
University of São Paulo



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--
Dr. Manfred S. Weiss
Macromolecular Crystallography
Helmholtz-Zentrum Berlin
Albert-Einstein-Str. 15
D-12489 Berlin
Germany

________________________________

Helmholtz-Zentrum Berlin für Materialien und Energie GmbH

Mitglied der Hermann von Helmholtz-Gemeinschaft Deutscher Forschungszentren e.V.

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Koch-Unterseher
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Frederking

Sitz Berlin, AG Charlottenburg, 89 HRB 5583

Postadresse:
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--
Dr. Manfred S. Weiss
Macromolecular Crystallography
Helmholtz-Zentrum Berlin
Albert-Einstein-Str. 15
D-12489 Berlin
Germany

________________________________

Helmholtz-Zentrum Berlin für Materialien und Energie GmbH

Mitglied der Hermann von Helmholtz-Gemeinschaft Deutscher Forschungszentren e.V.

Aufsichtsrat: Vorsitzender Dr. Volkmar Dietz, stv. Vorsitzende Dr. Jutta 
Koch-Unterseher
Geschäftsführung: Prof. Dr. Bernd Rech (Sprecher), Prof. Dr. Jan Lüning, Thomas 
Frederking

Sitz Berlin, AG Charlottenburg, 89 HRB 5583

Postadresse:
Hahn-Meitner-Platz 1
14109 Berlin
Deutschland


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