KLM (human computer interaction)

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KLM stands for Keystroke-Level Model, a hard science approach to human computer interaction, based on GOMS, developed by Card, Moran & Newell, and spelled out in their book The Psychology of Human Computer Interaction, 1983.

It is designed to be easier to use than other GOMS methods, such that companies who cannot afford HCI specialists can use it.

The CogTool project has developed an open-source tool to support KLM-GOMS analysis.

[edit] How does it work

The KLM-GOMS model is designed to be as straightforward as possible. The sequence of operations is modeled as a sequence of a small number of operations. Each operation is assigned a duration, which is intended to model the average amount of time an experienced user would take to perform it.

Kieras (1993, 2001) defines the following operations:

K, key press and release (keyboard) - 0.28 sec
P, point the mouse to something - 1.1 sec
B, button press or release (mouse) - 0.1 sec
H, hands movement from mouse to keyboard or reverse - 0.4 sec
M, mental thinking - 1.2 sec
W(t), wait time (system) - t msec

A mouse click would be written "BB" (button press, button release) while a sequence of keys 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).

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