Quantifying instrument errors in macromolecular X-ray data sets

An indicator which is calculated after the data reduction of a test data set may be used to estimate the (systematic) instrument error at a macromolecular X-ray source. The numerical value of the indicator is the highest signal-to-noise [I/sigma(I)] value that the experimental setup can produce and its reciprocal is related to the lower limit of the merging R factor. In the context of this study, the stability of the experimental setup is...