ISO 5725-1:2023

Overview

ISO 5725-1:2023, "Accuracy (trueness and precision) of measurement methods and results - Part 1: General principles and definitions," is published by the International Organization for Standardization (ISO). This standard lays the foundational concepts for evaluating the accuracy-understood as a combination of trueness and precision-of measurement methods, particularly those yielding continuous results. By providing definitions, principles, and a statistical model, ISO 5725-1:2023 ensures the clear communication and consistent application of accuracy criteria within laboratory and testing environments across multiple industries.

Key Topics

ISO 5725-1:2023 addresses several essential elements:

• Definitions and Terminology: Clarifies the concepts of accuracy, trueness, precision, repeatability, reproducibility, and bias.
• Accuracy Evaluation: Outlines the conditions, constraints, and organizational resources required to evaluate a measurement method or result.
• Measurement Methods: Focuses on methods that yield single-value results on a continuous scale, including those calculated from sets of observations.
• Statistical Model: Provides a foundational statistical framework and describes how terms like mean, bias, and standard deviation apply to measurement science.
• Organizational Framework: Recommends procedures for interlaboratory studies to obtain data on trueness and precision.
• Experiment Design: Details how to select laboratories, test items, and operating conditions for accuracy studies.
• Scope and Limitations: Excludes proficiency testing and reference item production, which are covered by ISO 13528 and ISO Guide 35, respectively.

Applications

ISO 5725-1:2023 is widely applicable across sectors where accurate, reliable measurements are critical. Applications of the standard include:

• Method Validation: Ensures that new or existing measurement methods meet defined accuracy criteria by assessing both trueness and precision.
• Quality Control: Supports comparison of measurement outcomes within a laboratory or between different laboratories, identifying sources of variation and systematic error.
• Accreditation and Standardization: Provides the basis for laboratory accreditation programs and consistent communication about measurement methods.
• Interlaboratory Comparisons: Guides the design and analysis of collaborative studies to establish common metrics for repeatability and reproducibility.
• Test Item Diversity: Applicable to gases, liquids, powders, and solid objects, whether naturally occurring or manufactured, provided test item homogeneity is considered.
• Ongoing Measurement Assurance: Supports long-term monitoring of measurement quality by identifying and quantifying sources of random and systematic error.

Related Standards

Several international standards complement the guidance and principles found in ISO 5725-1:2023:

• ISO 5725-2 to ISO 5725-6: Detailed procedures for determining precision, trueness, and practical applications stemming from Part 1’s principles.
• ISO 3534-1 & ISO 3534-2: Vocabulary and symbols for general and applied statistics, critical for correctly interpreting ISO 5725 terms.
• ISO 13528: Guidelines for statistical methods in proficiency testing by interlaboratory comparison-distinct from the scope of ISO 5725-1.
• ISO Guide 35: Reference item production and certification requirements, essential for establishing accepted reference values.

Practical Value

By standardizing terminology and frameworks for measuring accuracy, trueness, and precision, ISO 5725-1:2023:

• Enhances international comparability of measurement results
• Simplifies the validation and comparison of laboratory methods
• Reduces uncertainty in test outcomes
• Fosters trust in measurement data for regulatory, quality, and scientific decision-making processes

Adopting ISO 5725-1:2023 is essential for any laboratory or organization seeking consistent, high-quality measurement results that align with global best practices in metrology and quality assurance.