What is usability?

"Don't make me think."

Steve Krug

ISO guidance on usability defines it as "the extent to which a product can be used by specified users to achieve specified goals with effectiveness, efficiency and satisfaction".

In other words, usability measures the quality of a user's experience of your website. Is it easy to get around? Can tasks be completed without too much angst? Are visitors looking forward to coming back?

Jakob Nielsen says usability comprises "five quality components":

  • Learnability: How easy is it for users to accomplish basic tasks the first time they encounter the design?
  • Efficiency: Once users have learned the design, how quickly can they perform tasks?
  • Memorability: When users return to the design after a period of not using it, how easily can they reestablish proficiency?
  • Errors: How many errors do users make, how severe are these errors, and how easily can they recover from the errors?
  • Satisfaction: How pleasant is it to use the design?

See Nielsen's Usability 101: Introduction to Usability.

Benefits of usability

  • Websites and web services are much more effective.
  • Its not hard, expensive or onerous. Even some usability work will reap rewards.
  • Increased customer satisfaction and positive perception of the product and organisation.
  • Decreased post-implementation changes and costs.

Business cases

Usability testing often requires commitment from management. These links make the case for their buy in.

Including usability in the development processes

Any development process or method can incorporate a few user-centred activities to make it more user-centred. Usability activities can be put in place at different stages of the development process.

Most teams would already have some of these activities as a part of their normal work, but may call them something else or have a different way of doing them. The following is a summary of the most common development-stage activities.

Note that these aren't compulsory - you can pick and choose. See the links under "Resources" for more information on what to use, when and how.


Stakeholder meetings, define the purpose of the service/product/system, define user groups and their needs, create personas, determine the user experience.

Analysis and requirements

Focus groups, surveys, brainstorming, task analysis, determine the information needs and architecture, card sorting, walkthroughs, story boarding, user observation, interviews, frontline and helpdesk research, rapid prototyping.


Low- and high-fidelity prototyping, questionnaires, develop content and information architecture guidelines, expert review.


Contextual testing, think out loud protocol, explorative and scenario usability testing, post-testing questionnaires. Comparison testing.

Post development / continuous improvement

Web log/stats analysis, content and information audits (for accuracy, timeliness and consistency), periodical usability testing, user satisfaction research, user feedback, conducting user journals/diaries, frontline and helpdesk research and analysis, testing new concepts with user focus groups.



Usability.gov is a comprehensive American site providing good, basic overviews as well as

  • research-based guidelines
  • templates and examples
  • usability methods