A brief history of known tries to define usability. All information belongs to the specific party referenced.
linkISO 9241-11:2018: Usability
The extent to which a system, product or service can be used by specified users to achieve specified goals with effectiveness, efficiency and satisfaction in a specified context of use.
linkExpanded definition
Usability is relevant to:
- regular ongoing use, to enable users to achieve their goals effectively, efficiently and with satisfaction;
- learning, to enable new users to become effective, efficient and satisfied when starting to use a system, product or service;
- infrequent use, to enable users to be effective, efficient and satisfied with the system on each reuse;
- use by people with the widest range of capabilities;
- minimizing the risk and the undesirable consequences of use errors; and
- maintenance, in that it enables maintenance tasks to be completed effectively, efficiently and with satisfaction.
linkReference
Ergonomics of human-system interaction — Part 11: Usability: Definitions and concepts
linkDefinition of Usability as per Nielsen & Norman
Usability is a quality attribute that assesses how easy user interfaces are to use. The word “usability” also refers to methods for improving ease-of-use during the design process.
Usability is defined by 5 quality components:
- Learnability: How easy is it for users to accomplish basic tasks the first time they encounter the design?
- Efficiency: Once users have learned the design, how quickly can they perform tasks?
- Memorability: When users return to the design after a period of not using it, how easily can they reestablish proficiency?
- Errors: How many errors do users make, how severe are these errors, and how easily can they recover from the errors?
- Satisfaction: How pleasant is it to use the design?
linkReference
Usability 101: Introduction to Usability
linkUsability requirements for different aspects of the user experience
- Effective: How completely and accurately the work or experience is completed or goals reached
- Efficient: How quickly this work can be completed
- Engaging: How well the interface draws the user into the interaction and how pleasant and satisfying it is to use
- Error Tolerant: How well the product prevents errors and can help the user recover from mistakes that do occur
- Easy to Learn: How well the product supports both the initial orientation and continued learning throughout the complete lifetime of use
linkReference
Using the 5Es to understand users
Article photo by Joanna Kosinska on Unsplash