ISO 9241-20:2021

Overview

ISO 9241-20:2021 - "Ergonomics of human‑system interaction - Part 20: An ergonomic approach to accessibility within the ISO 9241 series" - provides a high‑level, ergonomic framework for integrating accessibility into the design of interactive systems. The second edition (2021) replaces the 2008 edition and shifts from prescriptive guidance toward referencing applicable parts of the ISO 9241 family and other international accessibility standards. It introduces the importance of accessibility to human‑system interaction, relates ISO 9241 principles to accessibility, describes accessibility‑focused activities aligned with human‑centred design (ISO 9241‑210), and points to standards relevant for accessible interactive systems.

Key topics

• Definitions and scope: clear definitions of accessibility, usability, user and user accessibility need as used in the ISO 9241 context.
• Ergonomic principles supporting accessibility: discussion of principles from across the ISO 9241 series (for example, suitability for the widest range of use, equitable use, robustness, self‑descriptiveness, learnability, controllability, approachability).
• Human‑centred design activities: accessibility‑focused steps mapped to ISO 9241‑210 processes - scoping, identifying users and contexts of use, specifying requirements, producing solutions, evaluation and iteration.
• Evaluation and conformity: emphasis on early and ongoing evaluation from the user’s perspective, defining accessibility measurements and verification criteria, and conformity assessment considerations.
• References and guidance sources: pointers to ISO 9241 parts and international accessibility guidance (Annex A and bibliography).

Practical applications

ISO 9241-20:2021 is a strategic guidance document for embedding accessibility into product and system development lifecycles. It helps teams:

• Translate user accessibility needs into measurable requirements and design targets.
• Plan and run accessibility‑focused research, design and evaluation activities.
• Integrate accessibility into procurement, project plans and conformity assessments.
• Harmonize ergonomic and accessibility objectives across products, services and environments.

Who should use this standard

• UX and interaction designers, accessibility specialists, usability engineers
• Product managers, system architects and developers
• Human factors/ergonomics practitioners and HCD teams (ISO 9241‑210)
• Procurement officers, compliance and standards professionals, policy makers

Related standards

Relevant parts of the ISO 9241 series referenced by ISO 9241‑20 include (but are not limited to): ISO 9241‑110, 112, 171, 220, 971 and other parts addressing visual, interaction and evaluation principles. See Annex A and the bibliography for major international accessibility guidance sources.

Keywords: ISO 9241-20, accessibility, ergonomics, human-system interaction, human-centred design, usability, accessibility standards.