Three New Accessibility and Web Design Standards ISO 9241 Parts 20, 151 and 171

2008 was a busy year for the committee dealing with international standards in usability and ergonomics with several new parts added to the influential series ISO9241 - Ergonomics of human-system interaction.  Three of these parts deal with accessibility and web design.

ISO 9241-20:2009  Accessibility guidelines for information/communication technology (ICT) equipment and services

This part of ISO 9241 is one of the introductory parts which applies to both hardware and software and aims to improve accessibility for use at work, in the home, and in mobile and public environments.  It is relevant to those responsible for:

• planning
• designing
• developing
• acquiring
• evaluating

information/communication technology (ICT) hardware, software and services. It covers the design and selection of equipment and services for people with a wide range of sensory, physical and cognitive abilities, including those who are temporarily disabled, and the elderly.  It contains general recommendations on:

• Managing development of accessible ICT equipment and services
• User characteristics (Vision, Hearing, Speech, Physical capabilities, Cognitive capabilities)
• Task characteristics
• Equipment and service characteristics
• Environmental characteristics.

ISO 9241-20:2009  Accessibility guidelines for information/communication technology (ICT) equipment and services

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ISO 9241-171:2008   Guidance on software accessibility

This standard is aimed at software designers and provides guidance on the design of software to achieve as high a level of accessibility as possible.   It replaces the earlier Technical Specification ISO TS 16071:2003 – Guidance on accessibility for human-computer interfaces and follows the same definition of accessibility - ‘usability of a product, service, environment or facility by people with the widest range of capabilities’.  It is synchronised with the US Human Factors & Ergonomics Society (HFES) 200.2 guidelines and applies to all software, not just web interfaces.  The key contents are:

• Rationale and benefits of implementing accessibility
• Principles for designing accessible software
• Sources of variation in user characteristics
• General guidelines and requirements including compatibility with assistive technology
• Inputs including keyboards and pointing devices
• Outputs including visual, audio and tactile outputs
• On-line documentation, “Help” and support services.

ISO 9241-171:2008   Guidance on software accessibility

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ISO 9241-151:2008  Guidance on World Wide Web user interfaces

This standard provides guidance on the human-centred design of software Web user interfaces with the aim of increasing usability.  This part of ISO 9241 sets out detailed design principles for designing usable web sites. The standard covers five areas:

• High-level design decisions and design strategy: These include deciding on the purpose of the site and how this is communicated to users? Who are the intended users and what are they trying to get from the site?
• Content design: What is the conceptual model underlying the site? How is it organised and how are issues such as privacy and personalisation addressed?
• Navigation components: How can the content be organised to help users navigate the site easily? How is search organised?
• Content presentation: How should pages and links be designed to help users achieve their goals?
• General design aspects: This includes issues such as internationalisation, how to provide usable help and building in error-tolerance.

The standard cross references other standards in the ISO 9241 series, which are also relevant to designers of web interfaces, and emphasises, in particular, the importance of ISO 9241-171 for ensuring that web interfaces are accessible.  It also references the W3C's Web Content Accessibility Guidelines.

ISO 9241-151:2008  Guidance on World Wide Web user interfaces

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