Dr Ellison is a Science Fellow at LGC, the UK National Measurement Laboratory for chemical and biological measurement. Originally qualified as a chemist, his current interests are primarily in statistics, measurement uncertainty and reference material certification. He is a co-author of EURACHEM guides on measurement uncertainty, metrological traceability and qualitative analysis and contributes to a range of IUPAC, ISO, CEN, BSI and other committees involving applications of statistics for measurement. He currently convenes a CCQM task Group on establishing key comparison reference values for international comparisons and is an IUPAC-appointed member of both the JCGM working group on guides for measurement uncertainty and that on Vocabulary for Metrology.