Participation in a proficiency test (PT) is an ideal way of objectively demonstrating the technical competence of a laboratory.  Achieving an acceptable result in such a comparison exercise provides concrete evidence of a laboratory’s claimed measurement capability. For laboratories working to ISO 17025 Standard, taking part in a proficiency test is a fundamental requirement of the standard.

Does your company

  • Need independent validation of your calibration capabilities and methods? 
  • Need to demonstrate competence to a third party?

NSAI NML can help

At the NSAI NML we can provide:
  • Tailored proficiency tests to meet individual needs
  • A large range of artefacts covereing most areas of metrology
  • An objective assessment of laboratory calibration capabilities
  • A proficiency test that meets INAB accreditation requirements

How does a proficiency test (PT) work?

In a typical PT, an artefact is firstly calibrated by the NSAI NML and then sent to the participating laboratory.

The calibrated value of the artefact is not known to the participant who in turn carries out a calibration using their own standards and procedures.  The participating laboratory submits a report of the calibration using their normal format.  
The normalised error of the participant’s results are used as a basis for judging the acceptability of the results.

The normalised error (En) is defined as:
En =   
(Difference in measured value between the participant & the reference)
(Uncertainty of the participant)1/2 + (Uncertainty of the reference)1/2

A result is considered to be acceptable when the absolute value of the value is less than unity.  Factors which may contribute to a high value include incorrect method, inaccurate measurement standards, incompetency, underestimation of uncertainty and mistake.
Ratio is therefore an extremely valuable indicator highlighting an error in the measurement system that requires immediate action, thus strengtheneing your measurement system and improving the quality of your measurements.