Usability

Draft

This article should be merged or at least coordinated with web usability - Daniel K. Schneider 18:31, 1 February 2011 (CET)

Definition

Usability is a term used to denote the ease with which people can employ a particular tool or other human-made object in order to achieve a particular goal. [...] In human-computer interaction and computer science, usability usually refers to the elegance and clarity with which the user interface of a computer program or a web site is designed. The term is also used often in the context of products like consumer electronics, or in the areas of communication, and knowledge transfer objects (such as a cookbook, a document or online help). It can also refer to the efficient design of a mechanical objects such as a door handle or a hammer. (Wikipedia: Usability - retrieved 17:30, 9 June 2006)

Usability can also refer to the methods of measuring usability and the study of the principles behind an object's perceived efficiency or elegance. (Wikipedia: Usability - retrieved 17:30, 9 June 2006 )

In more practical terms. ISO links usability to effectiveness, efficiency, and satisfaction, for a given product in a given context. According to the on-line Technical Layout & Design course (Technical Expressions, Inc,)

Usability specialists have expanded the ISO definition of usability, stating that a usable product is:

• easy to learn
• efficient to use
• provides quick recovery from errors
• easy to remember
• enjoyable to use
• visually pleasing

, retrieved 17:13, 26 January 2011 (CET).

See also:

• Cognitive ergonomics, Ergonomics (types of), HCI (human computer interaction)
• web usability, a sub-field of usability
• web accessibility, a sub-field of web usability that addresses the question of how to make websites usable by all sorts of people.
• User interaction and user interface design‎‎

Design methods

• See Design and usability methods and techniques

Usability measures

The ISO dimensions of efficiency, effectiveness and satisfaction can be operationalized in various ways: Sauro and Kindlund, (2005), in their SUM index use a mean of four (standardized) measures:

• efficiency is measured through task times
• effectiveness is measured both through number of errors and task completion
• satisfaction is measured with a short questionnaire based on Lewis (1991).

In other words, the SUM index can be summarized as:

usability = 0.25 * z-score (task time)
          + 0.25 * z-score-equivalent (N erros)
          + 0.25 * z-score-equivalent (task completion)
          + 0.25 * z-score (satisfaction)

Links

Resources

Larger usability sites (randomly sorted). Most include lot's of interesting materials.

• measuringusability.com
• sensible.com
• usability.gov
• usabilityfirst.com
• usabilityhome.com
• usabilityinstitute.com
• usabilitynet.org
• useit.com
• webcredible.uk.com
• demystifyingusability.com/
• usabilitytestingcentral.com/
• usabilitytestinghowto.blogspot.com/
• www.usabilitynews.com/ (aggregator)

General introductions

See also web usability and user interaction and user interface design

The US Research-Based Web Design & Usability Guidelines

“Throughout your Web design or redesign project, you should take advantage of what is already known about best practices for each step of the process. The Research-Based Web Design and Usability Guidelines, compiled through an extensive process of research and review, bring you those best practices.”

• Full book
• Index of individual chapters

Various interesting pieces

• Jeff Sauro has a series of interesting blog pieces, e.g.:
  • 97 Things to Know about Usability, by Jeff Sauro | September 7, 2010. (A nice list that includes links for further reading).
  • 5 Second Usability Tests by Jeff Sauro, November 9, 2010.
  • The Five Most Influential Papers in Usability
  • 25 Resources for Measuring Usability Dec 2010.

• Usability 101: Introduction to Usability by Jakob Nielsen, retrieved 16:51, 18 November 2010 (CET)

• Guerrilla HCI: Using Discount Usability Engineering to Penetrate the Intimidation Barrier by by Jakob Nielsen, 1994.

• User-Centered Design: The Fable of the User-Centered Designer, A nice story in PDF or ePub format by David Travis. (free)

• Professional and Technical Writing/Design/Usability and Professional and Technical Writing/Instructions (chapters from the Wikibook on professional and technical writing)

• User in Your Face, The Student Programmer's Before-and-After Guide to Usability and Usable Interface Design, by Jack Bellis.

• You Can't Innovate Like Apple by Alain Breillatt, 2008. (copy)

On Wikipedia

You may start from the Desing portal, a page that indexes most pages related to design including usability.

Sample pages:

• Usability
• Usability engineering
• Usability testing

Usability methods

• Methods table (usability.net, 40 popular methods sorted by design stages, introduction for each )
• Usability Methods (usability.gov, 13 most important methods tabulated with design stages)
• Both Usability and Usability engineering articles on Wikipedia include lists of methods (and pointers for further reading).
• The Usability Methods toolbox by James Hom
• Usability Evaluation
• Articles & Resources at UserFocus.co.uk
• sensible.com (Steve Krug)

On-line tools and usability services

(last checked on feb 2011)

• Usability Scorecard (measuringusability.com)
• UserTesting.com (for $39 hire a visitor that will send you a video message with problems found)
• crazyegg.com/ Get heat map analytics (starting at $20/month)
• feedbackarmy.com provides a questionnaire service (you submit questions and then get answers from 10 users, a questions test is $15)
• WebSort enables you to conduct remote card sorting online. (one free study, 10 participant limit)

Software

• Experience Capture Studio (A $18750 version includes hardware)
• LiveLogger, prior version of Experience Capture Studio. Possible free for non-commercial use, upon request). According to UseTube (2006), it “acts as a dynamic notebook that tracks the time for you and allows you to choose from certain actions so that when you choose that action, it marks the time and lets you make a note regarding the circumstances.”

Government

• Usability.gov (USA)

Standards

• ISO/TR 16982:2002 - "Ergonomics of human-system interaction—Usability methods supporting human-centered design"
• ISO 9241 - "Ergonomics of Human System Interaction" -
  • ISO 9241 Wikipedia summary

Bibliography

• Lewis, J. R. (1991). Psychometric evaluation of an afterscenario questionnaire for computer usability studies: The ASQ. SIGCHI Bulletin, 23, 78-81.

• Sauro, Jeff and Erika Kindlund, (2005). A Method to Standardize Usability Metrics into a Single Score, CHI 2005, PDF reprint