For resource evaluation, assay accuracy is critical, whereas precision can consider or be offset by sampling density. In quality assurance and quality control (QAQC) analysis, the assessment of the selected assaying method and its accuracy is often overlooked. Umpire samples provide an opportunity to test alternative assaying method outcomes and accuracy. However, often umpire sampling programs only demonstrate reproducible results for the same assay method at a different laboratory. If certified using a different assaying method, then certified reference materials (CRMs) can help to verify an assay method for accuracy. However, all commercial CRMs raise questions regarding the suitability of the CRM mineral matrix and the certification assay method. Work performed by Platina Resources Limited (Platina) on their scandium project in New South Wales (NSW), provides some insight into these issues with the comparison of Inductively Coupled Plasma (ICP) and X-ray Fluorescence (XRF) analytical data. It demonstrates typical small assaying accuracy issues for Ni and Co in nickel laterites, as well as significant inaccuracy when analysing for Sc in scandium rich laterite deposits. Platina refocused their QAQC work on accuracy, and this paper provides several valuable learnings, which have relevance to all mineral projects, as it is common for QAQC programs to focus on precision and performance without fully exploring assaying accuracy. CITATION: Horton, J A, 2019. The importance of assay method and accuracy a scandium case study, in Proceedings Mining Geology 2019, pp 4356 (The Australasian Institute of Mining and Metallurgy: Melbourne).