SIST EN ISO 4259-5:2024

Overview

EN ISO 4259-5:2024 (ISO 4259-5:2023, corrected 2024-03) defines a statistical procedure to assess the agreement between two different measurement methods that claim to measure the same quantitative property of petroleum and related products. It is intended for results obtained from a multi-sample–multi-lab study (MSMLS), such as interlaboratory studies (ILS) or proficiency testing programmes (PTP). The standard establishes the between-methods reproducibility - a limiting value for the difference between two results (one from each method) that is expected to be exceeded with a probability of 5% under normal operation. It also provides criteria for applying a simple linear bias correction to improve agreement.

Key Topics

• Scope and applicability: Analytical methods measuring quantitative petroleum properties in MSMLS (ILS or PTP data compliant with ISO 4259-1 / ISO 4259-3).
• Between-methods reproducibility: Definition and use as the limit for differences between method X and method Y after bias correction.
• Bias correction classes: Guidance for selecting no correction or linear corrections (constant, proportional, or both) and statistical tests to choose the appropriate class.
• Data suitability checks: Tests for sample variation, correlation between methods, extreme samples, and distribution of lab results.
• Statistical computations: Procedures for sample means, standard errors, weighted residuals, and confirmation of normality.
• Reporting requirements: Standardized output and worked examples (Annex A for ILS, Annex B for PTP).

Applications

EN ISO 4259-5:2024 is practical for professionals involved in measurement quality and method comparison in the petroleum sector:

• Laboratories and quality managers performing method validation or method transfer.
• Proficiency testing providers (PTP) and interlaboratory study (ILS) organisers analysing participant data.
• Method developers and standardisation bodies assessing whether two methods can be considered equivalent for a property.
• Regulators and contract partners who need objective acceptance criteria for method agreement and reproducibility.

Practical uses include establishing acceptance limits, determining if a simple bias correction is justified, improving comparability of historical and new methods, and documenting statistical evidence for method equivalence.

Related Standards

• ISO 4259-1 - requirements for ILS (reference in scope)
• ISO 4259-3 - requirements for PTP (reference in scope)
• EN ISO 4259-5:2024 - CEN endorsement of ISO 4259-5:2023

Keywords: EN ISO 4259-5:2024, ISO 4259-5:2023, between-methods reproducibility, bias correction, interlaboratory study, proficiency testing, MSMLS, petroleum measurement precision.