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License, which permits unrestricted use, distribution, and redistribution in any medium, provided that the original author and source are credited. For years, we have been trying to compare scattering patterns from different instruments. While this leads to reasonable results, there are precious few cases of true agreement despite the focus on data corrections (one example of agreement: [0]). My guess: we have not been considering coherence in these comparisons. Coherence is essential to all forms of scattering and diffraction, not just for coherent diffraction imaging and other fancy techniques. We have coherence when the electromagnetic waves in a particular area are in phase. All diffraction and scattering effects consider interference effects of these in-phase waves before and after their interaction with matter in the sample. All school experiments with double slits and diffraction gratings all assume coherence in the incomin