Usability

1.2.12 Give the precise meaning of the term usability and ccessibility
1.2.13 Usability problems with commonly used digital devices.
1.2.14 Methods that can be used to improve the accessibility of systems

IB Subtopics

Accessibility refers to the potential of a service, product, device, or environment to serve and meet the needs of as many individuals as possible. Frequently, accessibility is studies in parallel with disabled people and the use of various assistive technologies.

Usability refers to the potential of a product, application, or website to accomplish user goals. The term is not limited to computer science but extends to other products and services.

Usability should be analyzed by using eight quality components:

1. Complexity/Simplicity: Amount of effort to find a solution or get a result
2. Effectiveness: Comparison of user performance against a predefined level.
3. Efficiency: Number of errors, type of errors, and time needed to recover from errors.
4. Learnability: Time used to accomplish tasks on the first use.
5. Memorability: Time, number of button clicks, pages, and steps used by users when they return to the device after a period of not using it.
6. Readability/Comprehensibility: Reading speed
7. Satisfaction: Attitude of users toward applications after using them.

Possible usability problems can arise from:

• Faulty touch screens
• Poor speakers
• Inaccurate GPS data
• Small buttons
• Short battery life
• Small fonts
• Crowded screens
• Inaccurate sensors

Possible accessibility problems can arise from:

• Lack of support for visual impairment
• Lack of support for hearing and speech impairment
• Lack of support for learning disabilities and cognitive problems like dysgraphia or dyslexia, among others.
• Lack of support for mobility impairments or limited hand mobility