ISO 5725-2-2019 PDF

Full title and description

ISO 5725-2:2019 — Accuracy (trueness and precision) of measurement methods and results — Part 2: Basic method for the determination of repeatability and reproducibility of a standard measurement method. This part gives a detailed, practical description of the basic method for routine estimation of precision (repeatability and reproducibility) using collaborative interlaboratory experiments and guidance for personnel designing, performing or analysing such experiments.

Abstract

Part 2 of ISO 5725 amplifies general principles for designing experiments to estimate precision, describes the balanced uniform‑level collaborative experiment used to estimate repeatability and reproducibility standard deviations, and provides practical guidance for routine use. It applies to measurement methods producing a single continuous result (including results calculated from observations) and assumes the statistical model and definitions given in ISO 5725‑1.

General information

• Status: Withdrawn (superseded by a later edition — see note below).
• Publication date: 6 December 2019 (Edition 2, 2019).
• Publisher: International Organization for Standardization (ISO).
• ICS / categories: 17.020 (Metrology and measurement in general); 03.120.30 (Application of statistical methods).
• Edition / version: Edition 2 (2019).
• Number of pages: ISO listing: 69 pages; some national/adopted publications (e.g. BSI) show an alternate page count (≈78 pages) due to national front‑matter and formatting. Users should check the vendor copy for exact page count.

Scope

Provides the basic, routinely applicable experimental design and statistical treatment for estimating precision of standard measurement methods by collaborative interlaboratory experiments. The method is intended for standardized procedures in regular use, uses a balanced uniform‑level layout (same number of test results per laboratory, same sample levels), and assumes approximately normal distributions and the statistical model set out in ISO 5725‑1. It can also be used for preliminary precision estimates for non‑standardized methods.

Key topics and requirements

• Definition and estimation of repeatability and reproducibility standard deviations for measurement methods.
• Design of collaborative interlaboratory experiments: balanced uniform‑level layout, number of laboratories and replicates (as recommended in the standard).
• Statistical model and calculation procedures consistent with ISO 5725‑1 (definitions, notation and assumptions about error structure).
• Guidance on handling outliers and on reporting precision estimates for method validation and standardization.
• Practical instructions for carrying out routine precision studies and interpreting results for method acceptance.

Typical use and users

Used by national and industrial testing laboratories, standards developers, method authors, accreditation bodies, metrologists and statisticians to: (a) validate and quantify the precision of standardized measurement methods; (b) provide repeatability and reproducibility figures for method validation, certification and interlaboratory comparisons; and (c) support laboratories in demonstrating capability to use a method reproducibly.

Related standards

ISO 5725-2 is part of the ISO 5725 series. Key related documents include ISO 5725-1 (general principles and definitions) and other parts of ISO 5725 that cover modifications, practical use of accuracy values and specific applications; statistical vocabulary/notation is provided by the ISO 3534 series. Users should consult ISO 5725‑1 for the statistical model and definitions.

Keywords

accuracy, trueness, precision, repeatability, reproducibility, interlaboratory experiment, collaborative study, metrology, experimental design, statistical methods.

FAQ

Q: What is this standard?

A: ISO 5725-2:2019 describes the basic experimental and statistical method for determining the repeatability and reproducibility (precision) of a standard measurement method through collaborative interlaboratory experiments.

Q: What does it cover?

A: It covers the balanced uniform‑level design for collaborative studies, the calculation of repeatability and reproducibility standard deviations, guidance on performing the experiments, and practical instructions for routine precision estimation for methods producing a single continuous result.

Q: Who typically uses it?

A: Testing and calibration laboratories, method developers, accreditation bodies and statisticians use it when validating measurement methods, running proficiency/collaborative studies and reporting method precision.

Q: Is it current or superseded?

A: The 2019 edition (ISO 5725‑2:2019) has been superseded by a later edition published in December 2025 (ISO 5725‑2:2025, Edition 3). The 2019 text is therefore listed as withdrawn/replaced; users should consult the 2025 edition for the current, authoritative procedure.

Q: Is it part of a series?

A: Yes — ISO 5725 is a multipart series dealing with accuracy (trueness and precision). Part 1 covers general principles and definitions; other parts address modifications, use of accuracy values in practice, and related topics. Also, ISO 3534 provides the statistical vocabulary used across these parts.

Q: What are the key keywords?

A: Repeatability, reproducibility, precision, trueness, interlaboratory study, collaborative experiment, statistical model, metrology.