ISO 5725-2:2025

Overview

ISO 5725-2:2025 is part of the internationally recognized ISO 5725 series, focusing on evaluating the accuracy-specifically the trueness and precision-of measurement methods and results. This part of the standard provides a basic method for determining both repeatability and reproducibility of standardized measurement procedures. Developed by ISO Technical Committee 69/SC 6, ISO 5725-2:2025 delivers practical guidance for designing, executing, and analyzing collaborative interlaboratory experiments to numerically estimate the precision of measurement methods that yield results on a continuous scale.

The standard is essential for laboratories, quality managers, and method developers who aim to establish the reliability and comparability of results across different settings. It assumes adherence to the principles in ISO 5725-1 and is applicable to measurement procedures in regular, standardized use, as well as those undergoing preliminary evaluation.

Key Topics

• Precision Experiment Design:
  • Outlines the requirements for balanced, uniform-level collaborative experiments across multiple laboratories to assess method precision.
• Repeatability and Reproducibility:
  • Defines and addresses the consistent estimation of repeatability (within-laboratory) and reproducibility (between-laboratory) standard deviations.
• Personnel & Roles:
  • Offers structured guidance on the responsibilities of panel members, statistical experts, executive officers, and laboratory supervisors in conducting precision experiments.
• Data Collection and Analysis:
  • Establishes processes for collecting, recording, and scrutinizing measurement data, including treating outliers and reporting significant digits.
• Material Preparation:
  • Details considerations for selecting, preparing, and distributing homogeneous test materials to ensure consistent results.
• Statistical Model Usage:
  • Recommends the use of the statistical model described in ISO 5725-1, assuming that test result distributions are approximately normal.

Applications

ISO 5725-2:2025 is broadly applicable in situations where reliability and objectivity in measurement results are critical, including:

• Interlaboratory Comparisons:
  • Validating standardized methods in laboratories performing routine analysis in fields like pharmaceuticals, food safety, environmental testing, and industrial quality assessment.
• Quality Control and Method Validation:
  • Supporting quality assurance protocols that require numerical estimates of repeatability and reproducibility to satisfy regulatory or accreditation demands.
• Preliminary Method Evaluation:
  • Allowing estimation of method precision for newly developed or non-standardized procedures before widespread adoption.
• Establishing Measurement Uncertainty:
  • Contributing data for evaluating measurement uncertainty by providing precision estimates, supporting compliance with ISO 21748.

Related Standards

Several standards complement ISO 5725-2:2025 in the areas of statistical analysis of measurement methods:

• ISO 5725-1: Accuracy (trueness and precision) of measurement methods and results – General principles and definitions. This foundational document outlines definitions and overall principles.
• ISO 5725-3: Additional statistical methods for the estimation of intermediate precision and other components not covered in part 2.
• ISO 5725-4: Focuses on the determination of trueness in measurement methods.
• ISO 21748: Guidance for the use of accuracy data in estimating measurement uncertainty.
• ISO 3534 series: Provides vocabulary and symbols for statistics, applied statistics, and experimental design.

Practical Value

By adhering to the guidance in ISO 5725-2:2025, organizations can:

• Demonstrate the precision and reliability of their analytical methods.
• Facilitate data comparability and acceptance across laboratories worldwide.
• Fulfill requirements for method validation and laboratory accreditation.
• Reduce measurement errors and improve quality control.
• Build confidence among stakeholders in reported measurement results.

For laboratories and industries committed to high standards of measurement accuracy and reliability, implementing ISO 5725-2:2025 ensures robust assessment and consistent reporting of method precision.