ISO IEC TR 9126-2-2003 PDF

Full title and description

ISO/IEC TR 9126-2:2003 — Software engineering — Product quality — Part 2: External metrics. This technical report defines external metrics for measuring the external quality characteristics of software products (behaviour of running software as part of a computer-based system) and provides guidance and examples for applying those metrics during the software lifecycle.

Abstract

Part 2 of ISO/IEC 9126 provides a basic set of external metrics mapped to the external subcharacteristics defined in ISO/IEC 9126-1, explains how to apply metrics, and gives examples of metric application. The report is intended as a non‑exhaustive catalogue: organizations may select, adapt or define application‑specific metrics for evaluating product quality, requirements definition and quality measurement.

General information

• Status: Withdrawn; replaced by ISO/IEC 25023 (product quality measurement).
• Publication date: July 2003 (2003-07).
• Publisher: ISO and IEC (published under ISO/IEC JTC 1/SC 7).
• ICS / categories: 35.080 (Software engineering).
• Edition / version: Edition 2 (Technical Report, 2003).
• Number of pages: 86 pages (official ISO listing).

Scope

Defines external metrics applicable to running software (the behaviour of the software within a computer‑based system) for the external quality characteristics identified in ISO/IEC 9126‑1. The TR explains metric selection and application, offers a basic set of metrics for each external subcharacteristic, and includes examples showing how metrics can be used through the software product lifecycle. It does not prescribe fixed rating ranges — metric thresholds are to be defined per product, category and context of use.

Key topics and requirements

• Definition and classification of external metrics (metrics obtained from executing the software as part of a system).
• Metric examples for the external characteristics specified in ISO/IEC 9126‑1 (functionality, reliability, usability, efficiency, maintainability as observed externally, portability in use).
• Guidance on applying metrics across the product life cycle and on tailoring metrics to product category and context of use.
• Emphasis that the provided metrics are a basic, non‑exhaustive set and may be adapted or extended for domain‑specific needs.
• Advice not to assign universal graded thresholds within the TR — thresholds and ratings must be decided by stakeholders for each product or domain.

Typical use and users

Used by software developers, testers, evaluators, quality managers, acquirers and organisations defining product quality requirements or measurement programs. Typical activities include selecting and tailoring external metrics for acceptance testing, system evaluation, contract definition, benchmarking and continuous quality monitoring.

Related standards

ISO/IEC 9126 family: ISO/IEC 9126‑1 (Quality model) and ISO/IEC TR 9126‑3 (Internal metrics) / TR 9126‑4 (Quality in use metrics). The 9126 series has been superseded by the SQuaRE series; ISO/IEC 9126‑2:2003 has been replaced by ISO/IEC 25023 (2016) and the quality models consolidated in ISO/IEC 25010.

Keywords

external metrics, software product quality, ISO/IEC 9126, measurement, quality model, metrics application, external quality characteristics, SQuaRE, ISO/IEC 25023.

FAQ

Q: What is this standard?

A: ISO/IEC TR 9126‑2:2003 is the Technical Report (Part 2) of the ISO/IEC 9126 series that specifies external metrics for assessing software product quality — i.e., metrics observable when the software is executed within a system.

Q: What does it cover?

A: It covers a basic set of external metrics mapped to the external subcharacteristics of the ISO/IEC 9126 quality model, guidance on metric selection and application, and examples of metric use across the software lifecycle. The TR does not set universal numeric thresholds; those are defined per product/context.

Q: Who typically uses it?

A: Software developers, testers, evaluators, quality managers, acquirers and other stakeholders who need standardized guidance for selecting and applying external metrics to assess product behaviour and to support quality requirements and acceptance.

Q: Is it current or superseded?

A: ISO/IEC TR 9126‑2:2003 has been withdrawn; its scope and metric coverage were superseded by the ISO/IEC 25000 SQuaRE series (notably ISO/IEC 25023 for product measurement). It is therefore considered superseded for new projects, though its content remains useful for historical reference and for legacy processes.

Q: Is it part of a series?

A: Yes — it is Part 2 of the ISO/IEC 9126 series (Parts include the quality model, internal metrics, external metrics and quality‑in‑use metrics). The 9126 series was later restructured into the ISO/IEC 25000 (SQuaRE) series.

Q: What are the key keywords?

A: External metrics, software product quality, measurement, ISO/IEC 9126, metric selection, external quality characteristics, SQuaRE, ISO/IEC 25023.