Proficiency Testing” (PT) is a methodology used by Testing and Calibration laboratories, to objectively assess their competence to perform measurements. As such, it is an ISO/IEC 17025 requirement.
Interlaboratory comparisons (ILCs) are commonly used as the mechanism through which laboratory proficiency is tested. It should be noted however that ILCs only determine a difference between the participants and a Reference Value, but that does not quantify “Proficiency” against criteria of any kind. (What difference is acceptable?) Proficiency Testing therefore uses the results obtained in ILCs to evaluate participants’ performance against specified criteria.
Proficiency Testing reports a statistical number (score) which represents a participant’s “proficiency”. This is typically a “Z” or “Zeta” score for Testing Laboratories, or the “Normalised Error” (En ) value for Calibration Laboratories.
The NLA – SA offers several PT Schemes for both Calibration and Testing Laboratories as indicated on the website and is accredited to ISO/IEC 17043 as a Proficiency Testing Service Provider.
Testing PT Schemes
The NLA – SA offers a number of PT Schemes for various types of testing laboratories. These include:
Further information can be obtained by clicking here. Laboratories are also encouraged to contact the NLA – SA should they have PT requirements that are not currently being met and which could be developed.
Calibration PT Schemes
The NLA – SA also offer a number of PT Schemes specifically for calibration laboratories. They cover a wide number of metrology disciplines, artefacts and ranges and at measurement uncertainties ranging from typical calibration measurement uncertainties (CMCs) to those associated with multi-function, multi-range instruments.
The Schemes cover both the calibration of artefacts in participant laboratories, as well as several schemes in which the artefacts are calibrated on-site at the NLA – SA offices.
Schemes are typically run as “Star-schemes” where the PT artefact is sent to each participant after which it is returned to the NLA – SA.
Transport of the PT artefacts is usually undertaken by dedicated courier companies.
Additional information can be obtained here.