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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 and Software Quality

In the 1990s, battle lines were drawn between standards for software quality and standards for ergonomics. Within the ISO/IEC 9126 software quality standards, usability referred only to the design of a user interface. Some people working on the ISO 9241 standard so objected to the approach to usability in ISO/IEC 9126, that one national ergonomics committee threatened to reject an ISO 9241 standard if it contained so much as a citation of an ISO/IEC 9126 standard. But bridges have gradually been built with the broad view of usability being incorporated into software quality as quality in use (Bevan, 1999) and culminating in a joint working group to develop CIF standards in ISO.

In the new model for software quality in the draft ISO/IEC CD 25010 standard, the concept of quality in use has been broadened to embrace a wider range of issues than was common in usability (Bevan, 2009). While effectiveness and efficiency measure the positive benefits of productivity and goal achievement, the term safety has been used to refer to measures of the potential negative outcomes that could result from incomplete or incorrect output. The term flexibility has been added to refer to the need for usability in both planned and unplanned contexts of use and the need for usability for people with special needs. Flexibility can also include learnability, or how quickly and effectively a user interface can be learned. The standard also makes a distinction between usability from different stakeholder perspectives that result in different types of measures, including from the perspective of the end user achieving personal goals, the perspective of the organization achieving organizational goals, and the perspective of technical support achieving maintenance goals.

Note: The status of ISO standards is designated by the letters that precede the standard number. Draft ISO standards can include the following stages:

ISO documents below the status of a full standard include the following:

What are the benefits?

ISO/IEC CD 25010 (and ISO/IEC 9126-1 which it will replace) provides a comprehensive structure for the role of usability as part of software quality. The broader concept of quality in use increases the business relevance of usability in many situations.

What are the problems?

These standards provide a great way to integrate usability with quality, but do not help if quality is a low priority in your organization.

What should you use?

The requirements CIF (not yet published by ISO, but available from NIST, 2007) is a good guide on how to introduce usability requirements in an organization. Use ISO/IEC 25010 or ISO/IEC 9126-1 if your organization cares about product quality.

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