TSE ISO Guide 35

TSE ISO Guide 35 is a guide on the general and statistical principles for the certification of reference materials, with emphasis on certified reference materials. In metrology terms, reference materials are materials used to support measurement comparability; this document addresses the conceptual basis for assigning property values and evaluating the associated uncertainty.

The role of reference materials in measurement practice

In general technical use, reference materials are applied in instrument calibration, evaluation of test methods, and assignment of property values to materials. A certified reference material is especially valuable because its assigned value, together with the stated uncertainty, is documented in a way that supports traceability and confidence in the measurement process. These materials help laboratories check accuracy, compare methods, and demonstrate that results are consistent across different settings.

Why the statistical principles matter

The statistical emphasis in the title reflects the importance of how measurement data are evaluated during certification. In the production and certification of reference materials, concepts such as homogeneity, stability, and characterization are central to the credibility of the assigned property value and its suitability for a given use. This TSE edition has since been withdrawn, but the subject remains a key framework for understanding how reference materials support measurement quality.

• Supports confidence in calibration and quality control use cases.
• Provides a common comparison basis for evaluating test methods.
• Addresses the scientific and statistical justification for assigned property values.
• Explains core concepts that underpin consistency between laboratories.