A study conducted by the Laboratory Accreditation Bureau of noncompliances during accreditation assessments to ISO/IEC 17025—“General requirements for the competence of testing and calibration laboratories” found that the most cited clauses were found in section 5.4—“Methods and method validation.” This article attempts to clarify the intent of section 5.4 to help laboratories better select, validate, and manage their methods, procedures, and instructions. We’ll also look at uncertainty of measurement and how it relates to test or calibration measurements and data control.

The majority of noncompliances found by the Laboratory Accreditation Bureau were based on assessment data collected since 2012. The noncompliances were likely due, in part, to confusion caused by the terms “method” and “procedure,” which are used interchangeably in the standard, whereas in practice they are not.

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