Software usability
Usability is the measure of how easily a thing can be used (typically a software application or a piece of hardware). This is generally defined in terms of the needs of the users of the thing. Often, the intentions of designers directly conflict with these needs.
Usability addresses the full spectrum of impacts upon user success and satisfaction. Usability is accomplished through user-centered (not necessarily user-driven) design. The usability engineer provides a point-of-view that is not dependent upon designers' goals because the usability engineer's role is to act as the users' advocate. For example, after interacting with users, the usability engineer may identify needed functionality or design flaws that the designers had not anticipated.
Software Development magazine says:
- The International Standards Organization (ISO) defines usability as ?the effectiveness, efficiency and satisfaction with which specified users achieve specified goals in particular environments.?
Usability includes considerations such as:
- What do users want or need to do ?
- What is the general background of the users ?
- What is the context in which the user is working ?
- What has to be left to the machine ? What to the user ?
Answers to these can be obtained by conducting user and task analysis at the start of the project.
Other considerations include:
- Can users easily accomplish their intended tasks? For example, can users accomplished intended tasks at their intended speed?
- How much training do users need?
- What documentation or other supporting materials are available to help the user? Can users find the solutions they seek in these materials?
- What and how many errors do users make when interacting with the product?
- Can the user recover from errors? What do users have to do to recover from errors? Does the product help users recover from errors, for example, does software present informative, non-threatening error messages?
- Are there provisions for meeting the special needs of users with disabilities? (accessibility)
Examples of ways to find answers to these and other questions are user-focused requirements analysis, building user profiles, usability testing.
Usability is now recognized as an important software quality attribute, earning its place among more traditional attributes such as performance and robustness. Indeed various academic programs focus on usability. Also several have emerged, and traditional consultancy and design firms are offering similar services.
Usability professionals have their own Usability Professionals Organization.
Usability is the software specialization of the larger topic of human factors and ergonomics, although the term is also applied to document design.
See also
