Both command sources followed a Fitts' Law model of performance, though the smallest targets deviate slightly from this model (Figure 5).
Fitts' Law in two dimensions with hand and head movements.
There were multiple experiments with Fitts' law, when it was adapted to different Human Computer Interaction (HCI) devices -.
To get the task execution time we can divide certain task into small steps and with the help of Fitts' law to calculate how long it will take for the user to get from one place in the UI to another (by seeing it or by reaching it with some other HCI device).
These results are not consistent with the prediction that would be made by Fitts' law
(1954) alone, because the top button is farther away than the lower and middle buttons; however, such inconsistencies are not unexpected (e.g., see Welford, 1976, for a review).
Evaluation of Shoulder Position Transducers by Fitts' Law
and its modified versions (e.g., separating the target distance and width as two individual terms) have successfully characterized target acquisition performance in the physical world and in 2-D human-computer interfaces (see MacKenzie, 1992, for a review/and have also been shown to hold across a wide range of body movements and tasks (e.g., Andres & Hartung, 1989; Crossman & Goodeve, 1965/1983; Drury, 1975; Jagacinski & Monk, 1985: Kerr, 1978; Langolf, Chaffin, & Foulke, 1976).
For example, as predicted by Fitts' law
, one can decrease the time required to select a Web browser's controls by making the controls larger.
For human-computer interaction (HCI) design, Fitts' law
provides a practical method for comparing the performance of two pointing devices during identical targeting-type tasks, specifically the point-and-click operation (Douglas, Kirkpatrick, & MacKenzie, 1999).
has been widely used to predict movement times between a starting point and a finishing point in the presence of lags (Fitts & Peterson, 1964).
Results did not show a strong linear Fitts' law
relationship, especially at high difficulties.
Their study used a helmet-mounted sight as a computer input device and found Fitts' law
to adequately describe head movement.