XDS was used to reduce data from slow-rotation tilt series, first without any refinements in the IDXREF, INTEGRATE, or CORRECT steps permitted, and next with only refinements to crystal orientation permitted during these steps, to assess the impact on data reduction of accounting for unexpected changes in orientation. These refinements were performed on subsets of images in the series corresponding to 2.5 degrees of rotation of the crystal. In both cases, a constant mosaicity of 0.2 degrees was enforced. Data was scaled using XSCALE, and data reduction statistics were recorded from the log files generated from this process . Additionally, estimated crystal mosaicity for each frame was recorded from the INTEGRATE.LP file (log file from XDS's INTEGRATE step), and plotted against accumulated fluence and TEM stage rotation for each data treatment.