ISO 9241 Part 11: Guidance on usability

Citation

ISO 9241-11:1998 Ergonomic requirements for office work with visual display terminals (VDTs) -- Part 11: Guidance on usability.

Status

International Standard.

Lifecycle Phase

• Analyse the opportunity
• Build the context of use
• Create the user experience
• Track usage and improve

Type of Guidance

Principles and general recommendations.

Application Area

• Equipment
• User testing
• Software
• Process

Scope

This part of ISO 9241 introduces the concept of usability but does not make specific recommendations in terms of product attributes. Instead it defines usability as the:

“Extent to which a product can be used by specified users to achieve specified goals with effectiveness, efficiency and satisfaction in a specified context of use.”

One of the benefits of this approach is that it helps design teams plan for usability as part of the development lifecycle, by setting and measuring usability goals for the product. The standard describes how it can be applied to: specify and measure the usability of products; specify and evaluate usability during design; and specify and measure a work system in use. The standard includes five annexes: an example of how to specify the context of use; examples of usability measures; an example of a usability requirements specification; relationship to other international standards; and a bibliography. The term “satisfaction” in the definition of usability has been criticised as sounding weak: it sounds like “adequate” or “just good enough”, which is hardly a design goal worthy of aspiration. However, this is more an artefact of current usage: the dictionary defines satisfaction as “the feeling of pleasure that comes when a need or desire is fulfilled”.

Audience

Anyone that needs to set or measure usability goals for a system.

See Also

ISO 13407:1999 Human-centred design processes for interactive systems.

ISO/IEC 9126-1:2001 Software engineering -- Product quality -- Part 1: Quality model.

ISO/IEC TR 9126-2:2003 Software engineering -- Product quality -- Part 2: External metrics.

ISO/IEC TR 9126-3:2003 Software engineering -- Product quality -- Part 3: Internal metrics.

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