<p>This essay reflects on experiences gained in conducting courses on model calibration and uncertainty analysis. These topics are central to an understanding of what groundwater modelling can (and cannot) contribute to environmental decision-making. This is because education in these matters develops skillsets that are required for simulator-based harvesting of decision-pertinent information from site data. It also engenders a perspective that impacts the way in which decision-support modelling is understood, implemented and assessed by the industry at large.</p>