R-factors: Difference between revisions

109 bytes added ,  12 February 2008
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== Definitions ==
== Definitions ==
=== Data quality indicators ===
=== Data quality indicators ===
* R_sym and R_merge: the formula is (someone with LaTex knowledge please don't hesitate to fill in the formula!)
* R<sub>sym</sub> and R<sub>merge</sub> : the formula is (someone with LaTex knowledge please don't hesitate to fill in the formula!)
* Redundancy-independant version of the above: R_meas
* Redundancy-independant version of the above: R<sub>meas</sub>
* measuring quality of averaged intensities/amplitudes: R_p.i.m./R_mrgd-F
* measuring quality of averaged intensities/amplitudes: R<sub>p.i.m.</sub> and R<sub>mrgd-F</sub>


=== Model quality indicators ===
=== Model quality indicators ===
* R and R_free: the formula is (LaTex please )
* R and R<sub>free</sub> : the formula is (LaTex please )


== what do R-factors try to measure, and how to interpret their values? ==
== what do R-factors try to measure, and how to interpret their values? ==
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== what kind of problems exist with these indicators? ==
== what kind of problems exist with these indicators? ==
- (R_sym/R_merge) should not be used, R_meas should be used instead (explain why ?)
- (R<sub>sym</sub> / R<sub>merge</sub> ) should not be used, R<sub>meas</sub> should be used instead (explain why ?)


- R/R_free and NCS: reflections in work and test set are not independant
- R/R<sub>free</sub> and NCS: reflections in work and test set are not independant
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