This guidance document provides recommendations on how to handle measurements included in the inspection process. This document attempts to provide guidance to accreditation bodies when reviewing such inspection bodies. It is also suitable for providing recommendations on how inspection bodies should organize and carry out measurements. The main purpose of preparing this document is to ensure the validity of the measurements included in the inspection process. This document does not exceed the requirements specified in ISO/IEC 17020:2012 and is only dedicated to explaining the relevant requirements in accreditation. In addition to the provisions of ISO/IEC 17020:2012, no other requirements are mentioned in this document. The term "shall" in the document indicates that it reflects the mandatory requirements in ISO/IEC17020:2012. "Should" indicates a recommendation, a non-mandatory requirement, and a recognized approach provided by ILAC to meet the requirement. "May" means allowed (allowed). "Can" means possibility or ability. In this document, ISO/IEC 17020 refers to ISO/IEC 17020:2012, and ISO/IEC 17025 refers to ISO/IEC 17025:2017. In the case of this document, the inspection needs to comply with the requirements of ISO/IEC 17020, and the measurement may need to consider the requirements of ISO/IEC 17025. Both standards are developed by ISO CASCO and follow ISO CASCO principles and practices.