Estimation and uncertainty
Distinguish exact model values, rounded approximations and estimates from measurements. Declare the rounding rule, preserve information through calculations and unit changes, and interpret resolution, precision, accuracy and the stated uncertainty type without turning a report’s digits into guaranteed bounds.
Key knowledge
Measurement uncertainty describes the spread of values assignable to a specified measurand using the available information. A standard uncertainty expresses this spread as a standard deviation.
Conditions and scope
- Uncertainty is non-negative and is distinct from the unknown measurement error.
- An interval requires a stated coverage interpretation; one standard uncertainty is not a guaranteed bound.
Sources · 13
References
Sources retain their recorded scope. A source link alone does not establish verification of every statement.
Joint Committee for Guides in Metrology (JCGM)3 sources
- International Vocabulary of Metrology (VIM3)Joint Committee for Guides in Metrology (JCGM)Reference guideInternational Vocabulary of Metrology (VIM3) · Definitions with informative annotationsVIM, 2.26: Measurement uncertaintyVIM, 2.30: Standard measurement uncertaintyVIM, 2.16: Measurement errorVIM, 2.36: Coverage interval
- JCGM GUM-1:2023 · Guide to the expression of uncertainty in measurement · Part 1: IntroductionJoint Committee for Guides in Metrology (JCGM)Reference guide · PDF
- International vocabulary of metrology, third edition (2012)Joint Committee for Guides in Metrology (JCGM)Reference guide · PDF
National Institute of Standards and Technology (NIST)3 sources
- Technical Note 1297 · Section 6 · Expanded UncertaintyNational Institute of Standards and Technology (NIST)Reference guide
- Technical Note 1297 · Section 7 · Reporting UncertaintyNational Institute of Standards and Technology (NIST)Reference guide
- Technical Note 1297, section 5: Combined standard uncertaintyUS National Institute of Standards and TechnologyReference guide
- Chemistry 2e · Measurement Uncertainty, Accuracy, and PrecisionOpenStaxTextbook chapter
- The International System of Units (SI) · 9th edition · Version 4.01Bureau International des Poids et Mesures (BIPM)Reference guide · PDF
- A beginner’s guide to uncertainty of measurement · Guide 11, issue 2Stephanie A. Bell, National Physical LaboratoryTeaching resource · PDF
Evidence and review
VIM 2.26 and 2.30; NIST TN1297 5.1.
2026-10-10 · Uncertainty/standard-uncertainty terminology only; no uncertainty budget or numerical coverage probability has been established for a particular measurement.
Foundational review
2026-10-10 · Fresh primary-source inspection of the complete compact record, including every statement, equation, quantity and material condition, followed by independent AI editorial review. This check does not certify all linked lessons or every passage of every cited publication.
Sources from other places
Scope or convention differs
Standard uncertainty expressed through a standard deviation, distinct from measurement error.
The older guide focuses on an average and coverage factors; the repository measurand definition is broader.
National Physical Laboratory
- A beginner’s guide to uncertainty of measurement · Guide 11, issue 2 United KingdomEnglishShared standard
§2.3 Error versus uncertainty; §7.1 Standard uncertainty; §7.4 Coverage factor
- A beginner’s guide to uncertainty of measurement · Guide 11, issue 2
Related articles
Approximation, precision and measurement uncertainty ↗Entry details
Permanent link to this entry ↗- Record identity
- measurement-uncertainty
- Revision
- reference-core.1
- Published lesson seed
- measurement-estimates