Ulrich Leist is the Director and Founder of the Deutsches Referenzbüro für Ringversuche und Referenzmaterialien GmbH (DRRR) (German Reference Office for Proficiency Testing and Reference Materials). He is a scientist with a degree in chemistry and environmental science. He obtained his doctorate before taking up a position as a researcher at Harvard University (Cambridge, USA). Following this, he began working in the field of proficiency testing (PT). He has amassed over 20 years of experience in PT, reference material (RM) and accreditation. He obtained his first successful accreditation as a Pt-provider in 2006. He is an active member of numerous national and international working groups, and has contributed his expertise as a member of the ISO working group WG 57 for the ISO 17043:2023. He developed innovative statistical evaluation systems for PTs in the field of chemical, microbiological and organoleptic testing. He and his team have gained renown for developing PTs associated with the most difficult technical challenges. He and his team provide further support for standardisation organisations such as ISO by offering method validation ILCs and regularly publishing scientific results in peer-reviewed journals. During his tenure, DRRR has evolved into one of the major PT providers, delivering over 700 PT rounds annually to participants worldwide.