This Usability Standards cover several sub-domains, including:
- Accessibility
- Ease of use
- Ease of learning
- Memorability
- Error avoidance, handling, and recovery
- Efficiency of interactions
- Ergonomics
- Special mention must be made of Accessibility which focuses specifically on features that enable access for all, irrespective of infirmity or disability. Requirements in this sub-domain aim to enable access for people with disabilities and special needs or enable access through the use of assistive technologies such as computer screen readers.
When eliciting requirements for Usability, the following indicators should be taken into consideration:
- Average time needed for a specific type of user to complete a particular task correctly
- Number of transactions the user can complete correctly in a given time period
- Percentage of a set of tasks the user can complete correctly without needing help
- Number of errors the user makes when completing a transaction
- Number of attempts it takes a user to accomplish a particular task such as, for example, finding a specific function buried somewhere in the menus
- Delay or wait time when performing a task
- Number of interactions (e.g. mouse clicks, keystrokes, touch screen gestures) required to get to a piece of information or to accomplish a task
- There are Corporate and Technology Development design standards to address Usability.
