A standard operator in a keystroke-level model (KLM), K represents the act of striking a key on an input device like a keyboard or a mouse. The duration depends on the device and the skill of the user. A variety of quantitative estimates can be found in Card, Moran, and Newell (1980b, 1983).
keystroke-level model (KLM)
The simplest GOMS technique. It provides standard keystroke-level operators (D, H, K, M, P, and R) with estimates of duration and rules for placing the M (mental) operators. It abstracts away from the goal hierarchy, multiple methods, and selection rules found in other GOMS techniques. More information can be found in Card, Moran, and Newell (1980b, 1983).
See keystroke-level model.