Anomalous data-quality indicators. (a) Anomalous signal strength (Sano) of thaumatin 4.57 and 6.06 keV data sets for different numbers of indexed diffraction images. The horizontal line indicates an Sano value of 10, below which SAD phasing is difficult. The two vertical lines indicate the minimal numbers of indexed images required for structure determination using native-SAD in this study. (b) Correlation coefficient between the measured and calculated anomalous difference structure-factor amplitudes (CCanomodel versus data) for thaumatin data sets with minimal amount of data necessary for successful structure solution using native-SAD at the SwissFEL and the Swiss Light Source (SLS) (Leonarski et al., 2018).