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Charles D. Ehrlich (Fed)

Program Leader, International Legal Metrology

Dr. Charles (Chuck) Ehrlich is a Supervisory Physicist in the Office of Weights and Measures (OWM), Physical Measurement Laboratory (PML) at the National Institute of Standards and Technology (NIST). He currently serves as Program Leader of the International Legal Metrology Program in OWM.

During his almost 38-year tenure at the National Bureau of Standards (NBS) / National Institute of Standards and Technology (NIST), Dr. Ehrlich has played a key role in developing the nation’s first Leak Calibration Service (received NIST Bronze Medal Award), served for seven years as Group Leader of the NIST Pressure Group, served two years in the NIST Program Office, served for a year as the National Measurement and Standards Needs Assessment Coordinator, and for the past 20+ years has been the U.S. Representative (on behalf of the U.S. State Department) to the International Organization of Legal Metrology (OIML). He has served as 1st Vice President of the International Committee of Legal Metrology (CIML) since 2018, and Chairs the Regional Legal Metrology Organization (RLMO) Round Table.

As part of his role as U.S. CIML Member, Chuck played key roles in the development of the OIML Mutual Acceptance Arrangement for type evaluation certificates, and the subsequent OIML Certification System. He also led the effort to develop the OIML Guide 19 on The role of measurement uncertainty in conformity assessment decisions in legal metrology.

Chuck is very active in both the domestic and international metrology and legal metrology communities. He currently serves on the Joint BIPM-OIML Task Group on Digitalization, and consults on the CCU Task Group on Digitalization for core metrological terms.



  • William A. Wildhack Award (2007 NCSL International) “for his outstanding contributions to the field of Metrology”

  • Andrew Woodington Award (1999 Measurement Science Conference) for “Professionalism in Metrology”

  • NCSLI Best Paper Awards (Metrological Timelines in Traceability and Evolution of Philosophy and Description of Measurement Preliminary Rationale for VIM3)

  • DoC Bronze Medal (for establishing the nation’s first Leak Standards Program)


Uncertainty of Error: The Error Dilemma

Charles D. Ehrlich
Measurement error has historically been defined in the metrology community as a difference of 'values,' usually as a difference between a 'measured value' and a
Created October 8, 2019, Updated September 6, 2023