Traceability in measurements can be established through which of the following?

Traceability in measurements is a critical concept in ensuring that measurements can be related to national or international standards through an unbroken chain of comparisons. This chain typically starts from a recognized standard, such as a national measurement standard, down to the measurements made by laboratories or individuals.

The correct choice highlights the importance of stated references as well as maintaining unbroken chains of comparisons. By having clear references, it allows for the validation of measurement results and ensures that measurements remain consistent and accurate over time. This establishes a credible link to recognized standards, providing confidence that the results of measurements can be universally understood and accepted.

Using methods such as a single comparison or relying on outdated data lacks the robustness needed for establishing traceability. A single comparison may not capture the necessary complexity of variations in measurements, while outdated data would provide an invalid basis for current measurements. Furthermore, non-standardized references would not allow for reliable comparisons or validity, undermining the very foundation of traceability. Thus, the option of stated references and unbroken chains of comparisons clearly represents the appropriate and reliable means to establish traceability in measurements.