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International Standards for Usability Should Be More Widely Used

Nigel Bevan

Journal of Usability Studies, Volume 4, Issue 3, May 2009, pp. 106-113

Article Contents

Usability Assurance

Probably the best-known definition of usability is in ISO 9241-11: “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.” The intention when this standard was first drafted in 1988 was to specify the contents of usability assurance statements that would consist of test reports giving results for effectiveness, efficiency, and satisfaction in a specified context of use (Bevan & Holdaway, 1993). Unfortunately, some leading companies at that time did not want to be forced to produce usable products. For example, a large U.S. company threatened to use its influence to ensure that the standard was rejected unless it was redrafted as guidelines rather than requirements.

It was therefore reassuring to see the same concept reinvented in the U.S. 10 years later as the Common Industry Format (CIF) for usability test reports by a group of companies frustrated by the low profile of usability in product procurement (Bevan et al., 2002). This became the U.S. standard ANSI/NCITS 354 in 2001 (produced by the National Committee for Information Technology Standards in conjunction with the American National Standards Institute) and subsequently in 2006 the international standard ISO/IEC 25062 (as part of the series of standards on software quality published jointly by ISO and the International Electrotechnical Commission).

Work started in another ISO group in 2000 to provide usability assurance for machines used by the public and for consumer products. ISO 20282 was published as a preliminary standard for review in several parts in 2006 and 2007 (but not before a large German company lobbied hard to prevent publication of a standard that could possibly regulate the usability of consumer products). Work is just starting on reviewing and revising the ISO 20282 standards to make them more useful and effective. (You can volunteer through your national standards body if you would like to participate in the revision of these standards.)

What are the benefits?

Effectiveness and efficiency are easy to relate to business objectives, as they measure whether someone can use a product and how long they take to complete tasks (Bevan, 2006). User satisfaction is also an important objective for consumer products and motivates repeat usage, for example of a Web site.

What are the problems?

User testing to measure effectiveness and efficiency requires large numbers of participants, which can be expensive.

What should you use?

Strategic usability goals can have a big impact on design, so it is worth setting targets using ISO 9241-11 and the Requirements CIF (NIST, 2007) even if it is not easy to measure the targets. Consider using ISO 20282 to demonstrate the usability of public machines and consumer products.

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