Thus the statistics alone can never capture the full meaning of the fit. In judging the quality of a Rietveld fit, an expert human practitioner will not only look at the statistics and judge the correctness of the chemistry, but also consider what possible alternative models need to be compared against, and, ultimately, how the PXRD evidence helps address the wider research question. This is the capability that unsupervised AI Rietveld Refinement systems must possess to avoid incorrect interpretations, and to truly operate without human intervention.