The main idea of usability is that a system shall be designed with (generalized) users’ psychology and physiology in mind, to make that system:
- more efficient to use, so it takes less time to accomplish particular tasks
- easier to learn
- more satisfying to use
Definitions:
Capability of a product to be interacted with by specified users to exchange information between a user and a system via the user interface to complete the intended task. ISO-25010:2023
The capacity of a system to provide a condition for its users to perform the tasks safely, effectively, and efficiently while enjoying the experience. Wikipedia
Enable users to perform their tasks safely, effectively and efficiently while enjoying the experience.
Typical Acceptance Criteria
Scenario Response Measures from [Bass et al.]
The system should:
- provide the user with the features needed
- anticipate the user’s needs
- provide appropriate feedback to the user
The system’s response might be measured in one or more of the following:
- task time
- number of errors
- learning time
- ratio of learning time to task time
- number of tasks accomplished
- user satisfaction
- gain of user knowledge
- ratio of successful operations to total operations
- amount of time or data lost when an error occurs
What Stakeholders mean by usable
| Stakeholder | (potential) Expectation for usable |
|---|---|
| User | see the criteria above. More specifically: * functional-completeness * accessibility * correctness * visual and behavioural consistency * understandability * ease-of-use * functional-suitability * learnability * nice user-experience (maybe even more) |
| Product-Owner | - |
| Management | - |
| Developer | * understandable source-code and dependencies * an appropriate technology-stack * no (or at least predictable) side-effects when changing the system |
| Tester | * testability * predictable test behaviour |
| Admin | * easy to deploy and install, * installability * deployability |
| Domain-Expert | - |
| Others | - |
Qualities tagged with #usable
- Accessibility
- Accuracy
- Adaptability
- Affordability
- Anticipated Workplace Environment
- Appearance
- Appropriateness recognizability
- Attractiveness
- Availability
- Backward compatibility
- Clarity
- Code Readability
- Coherence
- Communicability
- Compatibility
- Compliance
- Conciseness
- Configurability
- Consistency
- Controllability
- Convenience
- Correctness
- Customizability
- Ease of Use
- Fault tolerance
- Faultlessness
- Features
- Functional Appropriateness
- Functional completeness
- Functional correctness
- Functional suitability
- Functionality
- Graceful degradation
- High availability
- i18n (Internationalization)
- Inclusivity
- Interaction capability
- Internationalization
- Interoperability
- Latency
- Learnability
- Legal Requirements
- Legibility
- Localizability
- Operability
- Preciseness
- Precision
- Readability
- Recoverability
- Reproducibility
- Responsiveness
- Self-descriptiveness
- Simplicity
- Standard Compliance
- Suitability
- Understandability
- Usability
- User assistance
- User engagement
- User error protection
- User experience
- User interface aesthetics
Requirements tagged with #usable
- Access Control via SSO
- Access find function in three seconds
- Accessible User Interface
- Accurate estimate of insurance contract rate
- Vehicle's position validity influences accuracy
- Appearance of mobile UI
- Clarity in technical documentation
- Compliance with WCAG accessibility guidelines
- Compliance with UI styleguide
- Configurable UI theme
- Consistent keyboard shortcuts
- Convenient online banking
- Core functions can be used on multiple OSs
- Cultural Sensitivity in Content
- Data Throughput for Visual Test System
- Detect inconsistent user input
- Display Data Based on Context
- Easily understandable acceptance test cases
- Easy UI
- Expressive error messages
- Inclusive User Testing
- Interruptable backend process
- Keep data on error
- New users learn to find articles on their own
- Restored to fully functional state 12h after complete failure
- Multilinguality Support
- Near instant search results
- Parallel Data Modification
- Recognize Assistive Technologies
- Available 7x24 with 99% uptime
- Restore Filter after Log In
- Unavailable for max 2 minutes
- Easily understandable generated code
- Usable Despite Color Blindness
- Usable on Factory Floor
- User Interface can be used in Current Browsers
- Usable With Gloves
- User tries to achieve primary function