How to use the Keystroke-Level Model to compare the efficiency of user interfaces
1. How to use the Keystroke Level Model
to measure and compare
the efficiency of user interfaces.
Sebastian Daum - Fortune Cookie Poland
2. About me
Sebastian Daum
• Immigrated from Germany to Poland 2 1/2 years ago
• Studied Digital Media
• UX Consultant at Fortune Cookie Poland since May 2011
• Happy to be here today!
sebastian.daum@fortunecookie.pl
14. KLM - How to use
1. Count all of the physical operations Point
Operator 1 [time]
+ Operator 2 [time] Click
+ Operator 3 [time]
+ Operator 4 [time]
Type
=
15. KLM - How to use
1. Count all of the physical operations Point
Operator 1 [time]
+ Operator 2 [time] Click
+ Operator 3 [time]
+ Operator 4 [time]
Type
2. Add mental acts where required Remember
+ Act of thinking / perception [time]
Perceive
=
16. KLM - How to use
1. Count all of the physical operations Point
Operator 1 [time]
+ Operator 2 [time] Click
+ Operator 3 [time]
+ Operator 4 [time]
Type
2. Add mental acts where required Remember
+ Act of thinking / perception [time]
Perceive
= Overall task execution time
26. KLM example
Assumption: Hands on keyboard
1. Home mouse H + 0.4 sec.
2. Point the mouse to the “From”-field P + 1.1 sec.
3. Click into “From”-field BB + 0.2 sec.
29. KLM example
8. Home mouse H + 0.4 sec.
9. Move mouse P + 1.1 sec.
10. Click on calendar icon BB + 0.2 sec.
30. KLM example
11. Move mouse P + 1.1 sec.
12. Click to change month BB + 0.2 sec.
13. Move mouse P + 1.1 sec.
14. Click to change month BB + 0.2 sec.
31. KLM example
15. Move mouse to 6th of december P + 1.1 sec.
16. Click to set date BB + 0.2 sec.
32. KLM example
17. Move mouse to “Time”-input box P + 1.1 sec.
18. Triple-click to select default value 3BB + 0.6 sec.
33. KLM example
19. Home keyboard H + 0.4 sec.
20. Replace default value with “19.00” 5K + 1.4 sec.
36. KLM example
23. Home mouse H + 0.4 sec.
24. Move mouse to 2nd “Search”-button P + 1.1 sec.
25. Click to see connections BB + 0.2 sec.
37. KLM example
The physical operators involved:
Only
H + P + BB + H + 7K + K + 8K + H + P + BB + P +
observable
BB + P + BB + P + BB + P + 3BB + H + 5K + K + K
keystroke + H + P + BB
actions
38. KLM example
The physical operators involved:
Only
H + P + BB + H + 7K + K + 8K + H + P + BB + P +
observable
BB + P + BB + P + BB + P + 3BB + H + 5K + K + K
keystroke + H + P + BB
actions
= 17.54 sec.
39. KLM example
The physical operators involved:
H + P + BB + H + 7K + K + 8K + H + P + BB + P +
BB + P + BB + P + BB + P + 3BB + H + 5K + K + K
+ H + P + BB
= 17.54 sec.
Insert mental operators
The
M + H + P + BB + H + 7K + K + 8K + M + H + P +
unobservable BB + M + P + BB + M + P + BB + M + P + BB + M +
part P + 3BB + H + 5K + K + M + K + M + H + P + BB
40. KLM example
The physical operators involved:
H + P + BB + H + 7K + K + 8K + H + P + BB + P +
BB + P + BB + P + BB + P + 3BB + H + 5K + K + K
+ H + P + BB
= 17.54 sec.
Insert mental operators
M + H + P + BB + H + 7K + K + 8K + M + H + P +
BB + M + P + BB + M + P + BB + M + P + BB + M +
P + 3BB + H + 5K + K + M + K + M + H + P + BB
= 27.54 sec.
63. + -
• Delivers accurate predictions
• Numbers to convince clients /
support sales
64. + -
• Delivers accurate predictions
• Numbers to convince clients /
support sales
• Easy to use
65. + -
• Delivers accurate predictions
• Numbers to convince clients /
support sales
• Easy to use
• Apply early in the design process
66. + -
• Delivers accurate predictions
• Numbers to convince clients /
support sales
• Easy to use
• Apply early in the design process
• No users involved
67. + -
• Delivers accurate predictions • Not applicable in all situations
• Numbers to convince clients /
support sales
• Easy to use
• Apply early in the design process
• No users involved
68. + -
• Delivers accurate predictions • Not applicable in all situations
• Numbers to convince clients / • Tedious estimation at millisecond level
support sales
• Easy to use
• Apply early in the design process
• No users involved
69. + -
• Delivers accurate predictions • Not applicable in all situations
• Numbers to convince clients / • Tedious estimation at millisecond level
support sales
• Easy to use
• Apply early in the design process
• No users involved
There is help!
70. Make KLM estimations quickly
• UI prototyping tool
• Automatically evaluates your design with a predictive human performance model
• Freeware