is a measure of how easily a thing (typically a software application
or a piece of hardware) can be used in the manner intended by the designers. Usability includes considerations such as:
- What do users want 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?
- How much training do users need?
- What documentation or other supporting materials are available to help the user?
- Can the user recover from errors?
- Are there provisions for meeting the special needs of users with disabilities?(Note: Is this item confusing usability with accessibility?)
Answers to these and other questions are determined through 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 treating usability as a core concern have begun to appear; see, e.g., the Human-Computer Interaction Program at Carnegie Mellon University.
Usability is the software specialization of the larger topic of human factors and ergonomics, although the term is also applied to document design.