What is ISO 4259‑3 about?
ISO 4259‑3 specifies the methodology for the regular monitoring of the test method precision achieved versus the precision published in the standard test method using data from proficiency testing schemes (PTSs) supported by the regular users of standard test methods.
The procedures in ISO 4259‑3 are designed specifically for proficiency testing (PT) conducted on standard test methods, having a published reproducibility, for petroleum and petroleum-related products, which are presumed to be homogeneous, and where the data distribution is approximately normal.
ISO 4259‑3 is applicable to properties of interest that are (known to be) stable over time and transport.
ISO 4259‑3 also specifies the methodology for the statistical comparison of standard deviation under reproducibility conditions achieved in PT programmes versus that published. The purpose of this comparison is to find out if the published reproducibility precision is representative of that achievable by the regular participants in the PT programmes.
ISO 4259‑3 also provides guidance on how to use a PT z-score to monitor an individual participant’s performance over time.
Who is ISO 4259‑-3 for?
4259-3 on PT conducted on standard test methods is relevant to:
- Petrochemical industry
- Lubricant laboratories
- Regulatory bodies
- Certification bodies
- Chemists
- Chemical engineers
Why should you use ISO 4259‑3?
Precision of measurement methods specifies the methodology for the design, execution and data processing of a one-time snapshot statistical study to arrive at precision estimates achieved by a random sampling of laboratories. This snapshot estimate is published in the standard test method as the expected precision. ISO 4259-3 defines PT as an evaluation of participant performance against pre-established criteria by means of interlaboratory comparisons.
ISO 4259‑3 explains the methodology for the utilisation of proficiency testing schemes to test the hypothesis that the precision achieved by the laboratories in the proficiency testing scheme is statistically consistent with the published precision.
Overall, ISO 4259-3 can help you establish a solid roadmap to ensure that laboratories validate the calibrating services that they offer. The accurate verification of published precision data is an efficient quality assessment on performance of laboratories that will set the base for the future precision expectations.
For a laboratory, compliance to these tests will also help you detect deviations and improve analytical accuracy and efficiency, while adhering to regulatory framework.