Safety Flashcards
1
Q
Errors in UI
A
- Excel carries formulas that must be entered with Ctrl Shift Enter not just Enter, every other edit you do is terminated by enter
- Caps Lock - when it’s enable on a keyboard, the letter keys produce uppercase letters
- The same action has diff meanings
- If a user means to type lowercase letters but doesn’t notice that caps lock is enabled
- Failing to correctly evaluate state of interface
2
Q
Error Prevention: Safety from Errors 1
A
- Avoid actions with similar descriptions: different things should look and act different
- Keep dangerous commands away from common ones e.g. Outlook 2003
3
Q
Safety from Errors 2
A
- Eliminate the modes but not always possible, modes do have some uses like making command sets smaller
- Increase visibility of mode:
- Status indicators must be visible in the users locus of attention
- Spring loaded mode:
- Shift key is spring loaded ver of uppercase mode
- Drag and drop
4
Q
Confirmation Dialogs
A
- Unfortunately common strategy for error prevention
- Not a good idea since efficiency is decreased because two buttons need to be pressed to confirm an action
- Slow downs UI
- Reversibility (undo) is better solution than confirmation
5
Q
User Control and Freedom
A
- Good UIs are explorable
- Learning by doing:
- An UI should encourage exploration making things more visible and consequences of errors less severe
- An easy, obvious way to get back to default/home view
- User should have ultimate control
6
Q
Clearly Marked Exits
A
- The simplest kind of user control is veto (the ability to cancel an operation
- Long operations should be cancellable
- All dialogs should have a cancel button
7
Q
Never Ask Me Again
A
- Many interfaces interrupt users with questions:
- If the answer is always the same, its inefficient
- Does improve user control
8
Q
Error Messages: Writing Error Message Dialogs
A
- Best error message is none at all
- Errors should be prevented e.g. not allowing a user to type in letters in a number field
9
Q
Error Messages: Be Precise and Comprehensible
A
- Be precise:
- Find out what’s really wrong and display a targeted message e.g. Line too long
- User can adapt
- Restate user’s input
- e.g. Cannot open file named paper.doc instead of Cannot open file so problem is detected immediately
- Speak the user’s language
- Not FileExceptionNotFound
- Hide technical details until requested
10
Q
Error Messages: Suggest Reasons and Solutions
A
- Give constructive help not just reporting the rror
- Why error occured and how to fix it
11
Q
Be Polite
A
- Be polite lol
- S