TSE ISO Guide 33

TSE ISO Guide 33 is a guide on how certified reference materials are understood and used in measurement science. It addresses the definitions of terms, principles for assessing the precision and trueness of a measurement process, and the use of certified reference materials in the definition and realization of measurement scales.

What a certified reference material means in practice

In general technical usage, a certified reference material is a reference material with one or more property values assigned together with an associated uncertainty and supporting documentation. Such materials are widely used to check measurement systems, compare method performance, and support consistency between laboratories. In this guide’s subject area, the SRM concept is not just about a physical sample; it also involves the certified value, traceability, and the intended measurement context.

Core measurement concepts addressed by the guide

• Precision describes how close repeated results are to one another; trueness describes how close the mean result is to a reference value.
• The definition and realization of measurement scales concern how units or scales are tied to a common reference.
• Reference materials provide a comparison basis in activities ranging from calibration to quality control.
• Such guides help users apply terminology consistently and avoid misinterpreting the role of reference materials.

From a broader technical perspective, this topic helps users evaluate measurement results not only as numbers but also in terms of meaning and reliability. The choice of material, the certification information, and the intended use all affect how a result should be interpreted. That is the practical value of TSE ISO Guide 33: it sets out the role of certified reference materials in a clear metrological framework.

This record represents the TSE guide standard adopted from ISO Guide 33 and later withdrawn. Its subject is therefore the technical framework for understanding and using certified reference materials within measurement systems.