CCalibration: A set of operations that establish, under specified conditions, the relationship between values of quantities indicated by a measuring instrument or measuring system, or values represented by a material measure or reference material, and the corresponding values realized by standards. [International Vocabulary of Basic and General Terms in Metrology (VIM; 1993) definition].
IInternal Measurement Assurance Program: Program of sufficient complexity, within an organization, to provide credibility to the measurement uncertainty and measurement result for which traceability is to be established. An internal measurement assurance program usually involves monitoring the performance (e.g., stability, reproducibility) of the instrument, standard, or measurement system, both before and after it is characterized or calibrated, used to obtain the traceable measurement result.
LLaboratory Accreditation: Procedure by which an authoritative body gives formal recognition that a laboratory is competent to carry out specific tasks. Accreditation does not itself qualify the laboratory to approve any particular product. However, accreditation may be relevant to approval and certification authorities when they decide whether or not to accept data produced by a given laboratory in connection with their own activities. (ISO Guide 58: Calibration and testing laboratory accreditation systems General requirements for operation and recognition, 1993).
NNational or International Standards: Measurement standards. Standards (national) recognized by a national decision to serve, in a country, as the basis for assigning values to other standards of the quantity concerned; standards (international) recognized by an international agreement to serve internationally as the basis for assigning values to other standards of the quantity concerned. [International Vocabulary of Basic and General Terms in Metrology (VIM; 1993)].
NIST Traceable Reference Material (NTRM): A reference material produced by a commercial supplier with a well-defined traceability to NIST established via criteria and protocols defined and documented by NIST and tailored to meet the needs of the metrological community to be served.
OOfficial NIST Program or Collaboration: NIST program or collaboration, officially approved by NIST management, in which NIST formally assures or certifies traceability of the results of measurements or values of standards.
Organizations that have authority and responsibility for variously defining, specifying, assuring, or certifying traceability: Any regulatory agency, standards developing organization, accreditation body, trade association or the like, which, by law or mutual agreement, is assigned or takes on authority and responsibility for some aspect of defining, specifying, assuring or certifying traceability.
PProficiency Evaluation MaterialsHomogeneous material or artifact that is used to test and evaluate the measurement performance of different measuring systems for specific tasks.
Provider of Result (of measurement) or Value (of standard): Individual or organization that supplies for use the result of measurement or value of standard for which traceability is being asserted.
RReference Material: Material or substance one or more of whose property values are sufficiently homogeneous and well-established to be used for the calibration of an apparatus, the assessment of a measurement method, or for assigning values to materials. [International Vocabulary of Basic and General Terms in Metrology (VIM; 1993) and ISO Guide 30:1992].
Result of Measurement: Value attributed to a measurand, obtained by measurement, where the measurand is the particular quantity subject to measurement and the value of the quantity is the magnitude of the particular quantity, generally expressed as a unit of measurement multiplied by a number.
SStandard Reference Materials: Certified reference materials (CRMs) issued under the NIST trademark. NIST Standard Reference Materials are characterized using state-of-the-art measurement methods and/or technologies for the determination of chemical composition and/or physical properties. The property values of an SRM are certified by a procedure that establishes traceability to an accurate realization of the unit in which the property values are expressed. Each certified value is accompanied by an uncertainty at a stated level of confidence. SRMs are issued by NIST with a certificate that reports the results of the characterization and indicates the intended use of the material. [See also International Vocabulary of Basic and General Terms in Metrology (VIM; 1993) and ISO Guide 30: 1992].
Standard Reference Data: Quantitative information, related to a measurable physical or chemical property of a substance or system of substances of known composition and structure, which is critically evaluated as to its reliability [Standard Reference Data Act, 15 U.S.C. 290 Sec. 2(a)].
Stated Reference: "Stated reference standard," where: (1) stated here means explicitly set forth in supporting documentation, and (2) a reference standard, which according to the International Vocabulary of Basic and General Terms in Metrology (VIM; 1993), is a standard generally having the highest metrological quality available at a given location or in a given organization, from which measurements there are derived.
Stated uncertainties: Uncertainty of measurement that: (1) fulfills the International Vocabulary of Basic and General Terms in Metrology (VIM; 1993) definition as the parameter, associated with the result of a measurement, that characterizes the dispersion of values that could reasonably be attributed to the measurand; (2) is evaluated and expressed according to the general rules given in the ISO Guide to the Expression of Uncertainty in Measurement; and (3) is explicitly set forth in supporting documentation.
TTest methods: Logical sequence of operations, described generically, used in the performance of measurements (International Vocabulary of Basic and General Terms in Metrology (VIM; 1993)) or specified technical procedures for performing a test (ISO Guide 2).
UUnbroken Chain of Comparisons: Complete, explicitly described, and documented series of comparisons that successively link the value and uncertainty of the result of a measurement with the values and uncertainties of each of the intermediate reference standards and the highest reference standard to which traceability for the result of measurement is claimed.
User of Result (of measurement) or Value (of standard):Individual or organization that receives for use the result of measurement or value of standard for which traceability is being asserted.
VValue of a Standard: The value attributed to a material measure, measuring instrument, or measuring system intended to define, realize, conserve, or reproduce a unit or one or more values of a quantity to serve as a reference [International Vocabulary of Basic and General Terms in Metrology (VIM; 1993)].