Undo for Mobile PhonesDoes Your Mobile Phone Need an Undo Key? Do You?
Marco Loregian, University of Milano-Bicocca (Italy)www.marcoloregian.net
Undo
• Well known function of PC applications
• Allows to revert (the effects of) commands
• Applied to user actions
• Different strategies
Undo modelsA coarse classification
What does “undo” mean when
operating with mobile phones?
...and I really mean phones,
not cool gadgets
The problem
• We need to know it in order to design usable (successful) devices
• How should we find it out?
• Undo is a user intention
• We surveyed users
Concerns in mind
• Reversibility (yes/no)
• Criticality (high/low)
The surveyOnline survey, 20 questions, 5 parts
1. Personal info (demographics)
2. Introduction (basic operations)
3. Scenario (multiple steps)
4. Reversed perspective
5. Conclusion (overall opinion)
The results
• Demographics
• Interesting facts from the survey
Full stats and comments in the paper
Demographics
0
20
40
60
80
15-20 21-25 26-30 31-35 36-40 41-45 46-50 51-551116
10
36
80
11
Age Distribution
45%55%
Gender
MaleFemale
146 respondents, 133 answered all questions
0
37,5
75,0
112,5
150,0
none one two three more4
25
116
1
Number of phones used regularly
0
15
30
45
60
None Basic Average Advanced Absolute
54
39
52
1
Computer Skills (wrt applications)
With respect to the diffusion of mobile phones, the sample is consistent with Italian population (istat.it)
Different computer skills may indicate
familiarity with different undo models
Highlights and selected survey
items
Confirmation
0
25
50
75
100
Yes No Yes, if...
18
33
97
Prompt for confirmation
66% want to know what they are undoing22% ask for a transparent implementation12% want to be warned in case of irreversibility
Granularity
Different preferences, variable granularity with respect to different situations… context awareness?
The same key has different behaviors in different moments, sometimes matching the End key
0
27,5
55,0
82,5
110,0
4
27
102
13
Question 8
0
17,5
35,0
52,5
70,0
1
18
61
17
47
Question 10
Timeline
• Very simple/intuitive interaction
• Linear and sequential undooperations undone one-by-one in reverse chronological order
Privacy and Responsibility
• Nothing hidden to me
• The responsible pays the price
0
27,5
55,0
82,5
110,0
Yes No
103
31
Can a SMS be deleted from your phone if you’ve not read it?
The verdict
0
10
20
30
40
50
60
70
Yes No Yes, if...
34
65
38
Would you like mobile phones to have an undo key?53% Yes
Conclusion
• Undo for mobile phones:
linear, sequential, with variable granularity and confirmation before execution
• Generalization of the results
More work
• Undo for email, a.k.a. retraction(poster yesterday)
• Undo for Ubiquitous Computingpublished at UIC’08, IDC’2008
Moral of the talk
If we had more ctrl+Z our lives might be better
undo!undo!undo!
Thank you,any question?
Undo for Mobile PhonesDoes Your Mobile Phone Need an Undo Key? Do You?
Marco Loregian, University of Milano-Bicocca (Italy)www.marcoloregian.net