IB Computer Science Topic 1.2.11 Usability and Accessibility Revision Notes (SL/HL)

IB Computer Science Topic 1.2.11 Usability and Accessibility Revision Notes (SL/HL) | RevisionDojo

Understanding Usability and Accessibility

What is Usability?

Definition

Usability

metric of how the technology or system suits everybody

Usability refers to the ease with which a user can interact with a system or product to achieve their goals. It can be measured via several key aspects:

Effectiveness: How well does the system enable users to achieve their goals?
Efficiency: How quickly can users complete tasks using the system?
Satisfaction: How pleasant is the user experience?

Note

Usability is not limited to software.
It applies to any product or system, including websites, applications, and physical devices.

Why is Usability Important?

User Satisfaction: A usable system leads to a positive user experience, which in turn increases satisfaction and loyalty.
Efficiency: Users can complete tasks more quickly, reducing frustration and increasing productivity.

Tip

When designing a system, always consider the user's perspective.
Test your design with real users to identify and address usability issues early.

Case study

Self Review

Can you identify examples of good and bad usability in products you use daily?
How might poor usability impact a business or organisation?

Common Usability Problems

Tip

Usability problems can be analysed using the following criteria:

Complexity/Simplicity: How easy is it for users to find solutions?
Effectiveness: Does the system meet predefined performance levels?
Efficiency: How quickly can users complete tasks?
Error Handling: How well does the system prevent and recover from errors?
Learnability: How quickly can new users become proficient?
Memorability: Can users easily remember how to use the system after a break?
Readability/Comprehensibility: Is the information easy to read and understand?
Satisfaction: How do users feel about the system after using it?

Some common usability problems may involve:

Complex interface/navigation: Users struggle to find the target page or function in poorly organised menus
Lack of Feedback: Is your username just wrong, or is it the password?
Inaccessible Design: Small icons and buttons make them harder to press
Lack of Error Handling: Imagine making a transaction in an online bank, and the program just freezes randomly
Poor Localisation: No option to choose the language is available
Unclear Instruction: What am I even supposed to type in the form?

Common Usability Problems in digital devices and their potential fixes:

Personal Computers (PCs):

Complex Interfaces: Menus confuse users → Use clearer layouts
Accessibility Issues: Standard inputs may not suit all → Offer alternatives like voice control
Health Concerns: Long use can cause strain → Promote ergonomic setups

Tip

When designing interfaces, prioritise clarity and simplicity to enhance user experience.

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Definition

Paywall

(on a website) an arrangement whereby access is restricted to users who have paid to subscribe to the site.

anim nostrud sit dolore minim proident quis fugiat velit et eiusmod nulla quis nulla mollit dolor sunt culpa aliqua

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat.

Duis aute irure dolor in reprehenderit

Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.

Note

Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam quis nostrud exercitation.

Excepteur sint occaecat cupidatat non proident

Nemo enim ipsam voluptatem quia voluptas sit aspernatur aut odit aut fugit, sed quia consequuntur magni dolores eos qui ratione voluptatem sequi nesciunt. Neque porro quisquam est, qui dolorem ipsum quia dolor sit amet, consectetur, adipisci velit.

Tip

Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat.

Lorem ipsum dolor sit amet, consectetur adipiscing elit.
Sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris.
Duis aute irure dolor in reprehenderit in voluptate velit esse cillum.

Unlock the rest of this chapter with a free account

Understanding Usability and Accessibility

What is Usability?

Definition

Usability

metric of how the technology or system suits everybody

Usability refers to the ease with which a user can interact with a system or product to achieve their goals. It can be measured via several key aspects:

Effectiveness: How well does the system enable users to achieve their goals?
Efficiency: How quickly can users complete tasks using the system?
Satisfaction: How pleasant is the user experience?

Note

Usability is not limited to software.
It applies to any product or system, including websites, applications, and physical devices.

Why is Usability Important?

User Satisfaction: A usable system leads to a positive user experience, which in turn increases satisfaction and loyalty.
Efficiency: Users can complete tasks more quickly, reducing frustration and increasing productivity.

Tip

When designing a system, always consider the user's perspective.
Test your design with real users to identify and address usability issues early.

Case study

Self Review

Can you identify examples of good and bad usability in products you use daily?
How might poor usability impact a business or organisation?

Common Usability Problems

Tip

Usability problems can be analysed using the following criteria:

Complexity/Simplicity: How easy is it for users to find solutions?
Effectiveness: Does the system meet predefined performance levels?
Efficiency: How quickly can users complete tasks?
Error Handling: How well does the system prevent and recover from errors?
Learnability: How quickly can new users become proficient?
Memorability: Can users easily remember how to use the system after a break?
Readability/Comprehensibility: Is the information easy to read and understand?
Satisfaction: How do users feel about the system after using it?

Some common usability problems may involve:

Complex interface/navigation: Users struggle to find the target page or function in poorly organised menus
Lack of Feedback: Is your username just wrong, or is it the password?
Inaccessible Design: Small icons and buttons make them harder to press
Lack of Error Handling: Imagine making a transaction in an online bank, and the program just freezes randomly
Poor Localisation: No option to choose the language is available
Unclear Instruction: What am I even supposed to type in the form?

Common Usability Problems in digital devices and their potential fixes:

Personal Computers (PCs):

Complex Interfaces: Menus confuse users → Use clearer layouts
Accessibility Issues: Standard inputs may not suit all → Offer alternatives like voice control
Health Concerns: Long use can cause strain → Promote ergonomic setups

Tip

When designing interfaces, prioritise clarity and simplicity to enhance user experience.

Definition

Paywall

(on a website) an arrangement whereby access is restricted to users who have paid to subscribe to the site.

anim nostrud sit dolore minim proident quis fugiat velit et eiusmod nulla quis nulla mollit dolor sunt culpa aliqua

Duis aute irure dolor in reprehenderit

Note

Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam quis nostrud exercitation.

Excepteur sint occaecat cupidatat non proident

Tip

Lorem ipsum dolor sit amet, consectetur adipiscing elit.
Sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris.
Duis aute irure dolor in reprehenderit in voluptate velit esse cillum.

1. System fundamentals2 subtopics

2. Computer organization1 subtopic

3. Networks1 subtopic

4. Computational thinking, problem-solving and programming3 subtopics

5. Abstract data structures (HL)1 subtopic

6. Resource management (HL)1 subtopic

7. Control (HL)1 subtopic

A. Databases4 subtopics

B. Modelling and simulation4 subtopics

C. Web science6 subtopics

D. Object-oriented programming (OOP)4 subtopics

IB Computer Science 1.2.11 Usability and Accessibility Notes

1. System fundamentals2 subtopics

2. Computer organization1 subtopic

3. Networks1 subtopic

4. Computational thinking, problem-solving and programming3 subtopics

5. Abstract data structures (HL)1 subtopic

6. Resource management (HL)1 subtopic

7. Control (HL)1 subtopic

A. Databases4 subtopics

B. Modelling and simulation4 subtopics

C. Web science6 subtopics

D. Object-oriented programming (OOP)4 subtopics

Understanding Usability and Accessibility

What is Usability?

Why is Usability Important?

Common Usability Problems

anim nostrud sit dolore minim proident quis fugiat velit et eiusmod nulla quis nulla mollit dolor sunt culpa aliqua

Duis aute irure dolor in reprehenderit

Excepteur sint occaecat cupidatat non proident

Unlock the rest of this chapter with a free account

Understanding Usability and Accessibility

What is Usability?

Why is Usability Important?

Common Usability Problems

anim nostrud sit dolore minim proident quis fugiat velit et eiusmod nulla quis nulla mollit dolor sunt culpa aliqua

Duis aute irure dolor in reprehenderit

Excepteur sint occaecat cupidatat non proident

Unlock the rest of this chapter with a free account