4.1 This practice sets the basic requirements for proficiency test programs in the chemical analysis of metals, ores, and related materials. It does not set specific procedural requirements, but does establish a framework for particular programs, including those with either small or large numbers of participants.

4.2 The data from proficiency testing programs can be used for value assignments for in-house reference materials developed in accordance with Guide E2972.

4.3 Most accreditation bodies require that laboratories participate regularly in proficiency testing programs that they have accepted for this purpose. Therefore, it is essential that each program comply with accepted principles including technical requirements, statistical procedures (see Annex A1), and quality management (see Annex A2).