或譯：可用性、優使性

• 產品的一組屬性
  • ISO 9241-11: “[Usability refers to] 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.”
  • Jakob Nielsen(1993): 使用性並不是一種使用者介面的單一維度屬性。傳統上，使用性有五個不同屬性：可學性、效率、可記憶性、錯誤率、滿意度。
    It is important to realize that usability is not a single, one-dimensional property of a user interface. Usability has multiple components and is traditionally associated with these five usability attributes: learnability, efficiency, memorability, errors, satisfaction. - Jakob Nielsen, Usability Engineering, 1993, p. 26
• 產品使用經驗的一種屬性
  • Usability.gov: In general, usability refers to how well users can learn and use a product to achieve their goals and how satisfied they are with that process. http://usability.gov/basics/
• 產品好用/易用的程度
  • Janice (Ginny) Redish & Joseph Dumas(1999): Usability means that the people who use the product can do so quickly and easily to accomplish their own tasks. This definition rests on four points: (1) Usability means focusing on users; (2) people use products to be productive; (3) users are busy people trying to accomplish tasks; and (4) users decide when a product is easy to use. - Janice (Ginny) Redish and Joseph Dumas, A Practical Guide to Usability Testing, 1999, p. 4
  • Steve Krug(2000): After all, usability really just means that making sure that something works well: that a person of average (or even below average) ability and experience can use the thing - whether it's a Web site, a fighter jet, or a revolving door - for its intended purpose without getting hopelessly frustrated. - Steve Krug, Don't Make Me Think, 2000, p. 5
• 一種設計方法
  • UPA: “Usability is an approach to product development that incorporates direct user feedback throughout the development cycle in order to reduce costs and create products and tools that meet user needs. There are many definitions of usability from books by usability professionals.” ( http://www.upassoc.org/usability_resources/about_usability/definitions_of_usability.html 2010-11-07 )
• 混合定義
  • Whitney Quesenbery: Usability starts with a philosophy - a belief in designing to meet user needs and to focus on creating an excellent user experience - but it is the specific process and methodology that produce the real goal of usability. A new usability process starts by looking at who uses a product, understanding their goals and needs, and selecting the right techniques to answer the question, “How well does this product meet the usability requirements of our users?” - Whitney Quesenbery http://www.wqusability.com/articles/getting-started.html

• Jakob Nielsen
• Steve Krug

• Heuristics Usability Evaluation 準則式使用性評估
• System Usability Scale(SUS) 系統使用性量表

• http://www.usability.gov/
• http://www.usabilitynet.org/
• http://www.d.umn.edu/itss/support/Training/Online/webdesign/usability.html

• http://www.usabilitybok.org/
• http://universalusability.com/index.html

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