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We can plot (Diederichs <ref name="Di06">K. Diederichs (2006). Some aspects of quantitative analysis and correction of radiation damage. Acta Cryst D62, 96-101 [http://strucbio.biologie.uni-konstanz.de/strucbio/files/Diederichs_ActaD62_96.pdf]</ref>)

We can plot (Diederichs <ref name="Di06">K. Diederichs (2006). Some aspects of quantitative analysis and correction of radiation damage. Acta Cryst D62, 96-101 [http://strucbio.biologie.uni-konstanz.de/strucbio/files/Diederichs_ActaD62_96.pdf]</ref>)

−<math>

+ <math>

R_{d} = \frac{\sum_{hkl} \sum_{|i-j|=d} \vert I_{hkl,i} - I_{hkl,j}\vert}{\sum_{hkl} \sum_{|i-j|=d} (I_{hkl,i} + I_{hkl,j})/2}

R_{d} = \frac{\sum_{hkl} \sum_{|i-j|=d} \vert I_{hkl,i} - I_{hkl,j}\vert}{\sum_{hkl} \sum_{|i-j|=d} (I_{hkl,i} + I_{hkl,j})/2}

−</math>

+ </math>

which gives us the average R-factor of two reflections measured d frames apart. As long as the plot is parallel to the x axis there is no radiation damage. As soon as the plot starts to rise, we see that there's a systematical error contribution due to radiation damage.

which gives us the average R-factor of two reflections measured d frames apart. As long as the plot is parallel to the x axis there is no radiation damage. As soon as the plot starts to rise, we see that there's a systematical error contribution due to radiation damage.

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=== Comparing two sets of structure factor amplitudes or intensities ===

=== Comparing two sets of structure factor amplitudes or intensities ===

The following is symmetric, and suitable for comparing two data sets, or two model amplitudes:

The following is symmetric, and suitable for comparing two data sets, or two model amplitudes:

−<math>

+ <math>

R=\frac{\sum_{hkl}\vert F_{hkl}^{i}-F_{hkl}^{j}\vert}{\sum_{hkl} 1/2 (F_{hkl}^{i}+F_{hkl}^{j})}

R=\frac{\sum_{hkl}\vert F_{hkl}^{i}-F_{hkl}^{j}\vert}{\sum_{hkl} 1/2 (F_{hkl}^{i}+F_{hkl}^{j})}

−</math>

+ </math>

for amplitudes, and analogously for intensities:

for amplitudes, and analogously for intensities:

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