
Teaching Assistent physics, Univ Botswana (1982)
Grade I qualified teacher in physics (1985-)
Technical responsible scientist for temperature and humidity standards of NMi/VSL (1986-2004)
Teacher at and writer of courses of NMi/VSL (1989 -2005)
Representing NMi/VSL at the CCT (1996-2003) and rapporteur for CCT-meetings of 2000 and 2001. Chairman CCT Werkgroep 8 (2002-2004)
Chairman EUROMET TC-Therm (2001-2004)
Owner MartinDeGroot Consultancy (2004-2005 & 2008-)
Project- and quality manager Contell-IKS (2005-2007)
Teacher for Kelvin-Trainingen (2004-)
ISO/IEC 17025 Technical assessor for RvA (1987-),UKAS (1995-),SANAS (2003), PCA (2005), ISRAC (2004-2006), INAB (2010-2011) and BELAC (2004-)
ISO/IEC 17025 lead assessor for RvA (2008-) and INAB (2010-2011)
Many of the afore-mentioned Conformity Assessment Bodies (CAB's) are members of European Accreditation and all are signatories to the ILAC MRA
Author of some 100 publications on thermometry, humidity and uncertainty

Bachelor of Science, University of Utah, Salt Lake City 2005
Metrologist at Hart Scientific/Fluke Calibration, American Fork, UT, USA (2000-2005)
Sr. Metrologist at Fluke Calibration, American Fork, UT, USA (2005-2015)
Head laboratorium at Fluke (UK) Ltd., Norwich, UK (2015-2018)
Leader Metrology Temperature, Pressure and airflow EMEA Fluke Nederland (2018-2020)
Owner Harper Metrology (2020 –)
Technical Expert/Assessor at RvA (2020 - ), INAB(2020 -)
Teacher and developer Kelvin Training (2021 -)

Secondary teacher training Mathemathics and Physics (PTHN 1989-1993)
Teacher at C+B advice and expertice, telematics and lighting technique (1993-1997)
Teacher VSO/LOM De Stolberg Eindhoven maths and physics (1997-1999)
VSO Physics teacher and teachertrainer Katsina State Nigeria (1999-2001)
Teacher at Stebo Utrecht maths and physics (2002-2005)
Teacher at Gymnasium Beekvliet St. Michielsgestel maths (2007-2011)
Developer for e-leaning courses at Kelvin-trainingen (2013-)
Courses for QAducation Vof are in collaboratorion with Ing. Sascha van de Ven