Keystroke-level model: Difference between revisions

Revision as of 03:51, 1 April 2008

Revision as of 04:14, 1 April 2008

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* '''K''', key press and release (keyboard)

Best Typist (135 wpm) --- 0.08 seconds

Good Typist (90 wpm) --- 0.12 seconds

Poor Typist (40 wpm) --- 0.28 seconds

Average Skilled Typist (55 wpm) --- 0.20 seconds

Average Non-secretary Typist (40 wpm) --- 0.28 seconds

Typing Random Letters --- 0.50 seconds

Typing Complex Codes --- 0.75 seconds

Worst Typist (unfamiliar with keyboard) --- 1.20 seconds

* '''P''', pointPoint the mouse to somethingan object on screen --- 1.110 secseconds

* '''B''', buttonButton press or release (mouse) --- 0.110 secseconds

* '''H''', hands movementHand from mousekeyboard to keyboardmouse or reversevice versa --- 0.440 secseconds

* '''M''', mentalMental Preparation thinking --- 1.220 secseconds

* '''W(t)''', wait time (system) - t msec

A mouse click would be written "BB" (button press, button release) while a sequence of keys3 keyboard key presses is "KKK..." or "T(n)" ("T" stands for "type").

A common operation that involves pointing and clicking something on the screen would be written "MPBB" (think, point, press, release).

KLM is not the only technique for evaluating interfaces, but it can be used to compare the speed of two different interfaces designed to accomplish the same task.

===Testing Steps===

The following 11 steps were developed based upon the methodologies and ideas of Kieras and Olson-Olson and describe the proper approach to calculate the time it takes to complete a task by using a computer interface and hardware.

Step 1--Obtain a working prototype of computer interface or a step by step operational description of a task.

Step 2--Identify the goals or the desired outcome of work .

Step 3--For each of these goals, find subgoals or tasks that achieve the main goals.

Step 4--Identify methods to main goals and all subgoals.

Step 5--Convert description of methods to pseudo-code (the terminology that is described above).

Step 6--State any and all assumptions used in the making of pseudo-code and goals.

Step 7--Determine appropriate mental or keystroke operators for each step.

Step 8--Assign time values to mental or keystroke operators.

Step 9--Add up execution times for operators.

Step 10-Adjust total time of task to be sensitive by age of expected.

'''Age''' '''Time Adjustment Multiplier (Multiply task time by this value)'''

18-30 Use as is

30-40 ???

40-55 By 1.4

55-60 By 1.7

> 65 By 2.2

Step 11-Verify validity of results

==Problems with this model==