Lecture 7: Errors

Question 1

What are the four error types?

Answer 1

1. Slips
2. Lapses
3. Mistakes
4. Mode

Question 2

What are Slip errors?

Answer 2

Slips are errors with regards to a failure of execution.

Question 3

What are Lapse errors?

Answer 3

Lapses are errors with regards to a failure of memory.

Question 4

What are Mistakes?

Answer 4

Mistakes are errors with regards to using a wrong procedure to try achieve a certain goal.

Question 5

What are two types of Slip errors?

Answer 5

1. Capture

2. Description

Question 6

What is the Capture slip error?

Answer 6

A capture slip error is when you start executing one sequence of actions, but drift into another, usually more familiar sequence.

Question 7

What is the Description slip error?

Answer 7

A description slip error is when two actions are very similar, the users accidentally substitutes one for another.

Question 8

What are the three types of lapse errors?

Answer 8

1. Loss of intention
2. Omissions due to interruption
3. Omissions due to already-satisfied goal

Question 9

What are Modes?

Answer 9

Modes are states in which actions have different meanings e.g. CAPS LOCK.

Question 10

What are Mode errors?

Answer 10

Mode errors are generally slips (errors) in the execution of a learned procedure, caused by failing to correctly evaluate the state of the interface.

Question 11

What are the two steps that can be taken to avoid capture and description slips?

Answer 11

1. Avoid actions with very similar descriptions, the opposite of the consistency heuristics - different things should look and act differently.
2. Keep dangerous commands away from common ones

Question 12

What are the three steps that can be taken to avoid mode errors?

Answer 12

1. Eliminate modes
2. Increase visibility of mode
3. Spring-loaded or temporary modes

Question 13

What are the three steps that can be taken to avoid lapses?

Answer 13

1. Keep procedures short
2. Minimise interruptions
3. Using forcing functions

Question 14

What are the four general steps which can be taken for error prevention?

Answer 14

1. Disable illegal commands
2. Use menus and forms, no command languages
3. All needed information should be visible
4. Use combo boxes, not text boxes

Question 15

What are the two key points around confirmation dialogues?

Answer 15

• Frequent commands should avoid confirmations.

- Operations that are very hard to reverse may deserve confirmation.

Question 16

When writing error messages what are the FIVE key aspects?

Answer 16

1. Be precise
2. Restate user’s input
3. Speak the user’s language
4. Suggest Reasons and Solutions (constructive help)
5. Be polite (avoid loaded words and non-blaming)

Question 17

What are the four simplifying data entry design patterns?

Answer 17

1. Autocomplete
2. Forgiving Format
3. Input Hints
4. Event Calendar