How should Fitts' Law be applied to human-computer interaction?

Usability of Graphical Icons in the Design of Human-Computer Interfaces

“…As Fitts' Law combines the position information and icon size information, it continues to provide a useful metric for designers to make best use of screen real estate in new interfaces. As several authors, such as Gillan et al (1992), Epps (1986), and McKenzie (1992), pointed out, Fitts' Law should and does apply in one form or another, as it predicts a number of movement actions on a computer interface. With the slope coefficients well within the range reported in other experiments, this was confirmed.…”

“…Quoted values in the literature range from about 90 (Card et al, 1978;Gillan et al, 1992;Mackenzie, 1992) to 392 (Epps, 1986). Different tasks (e.g., point and click vs. drag and drop) may well give rise to detailed differences in movement times, but all appear to be manifestations of Fitts' Law, especially if the definition of target size is made specific to the task (Gillan et al, 1992). Interestingly, in the two experiments (1 and 2), which found the best fit in terms of r 2 , the coefficients were almost identical at about 200 msec/bit.…”

“…Gillan, Holden, Adam, Rudisill, and Magee (1992) investigated point-click and point-drag movements and showed that the structure of such movements depends on the specificity of the performed tasks, including knowledge of the users' sequence of movements, direction of movement, typical movement amplitudes, and target sizes. Our research goes beyond the studies reported by Gillan et al (1992), investigating the aspects of timing of target presentation and the way target grouping influences the degree to which other processes than those accounted by Fitts' Law need to be taken into account. In particular, possible components of icon acquisition were examined, where cognitive and motor functions may overlap or interfere under some circumstances.…”

Cursor Control Device Test Battery: Development and Application

“…Task 5. Text selection (Gillan et al, 1992). This task is similar to text selection in text editor software.…”

“…The fifth task from ISO 9241-9 (tracing task) was not incorporated for the testing presented in this paper because it did not map strongly to the types of operations envisioned for Exploration missions. Non-ISO tasks that had been used in previous evaluations were also added, including a multi-size and multidistance pointing task (Everett, Holden & Whitmore, 2005), a text selection task (Gillan Holden, Adam, Rudisill, & Magee, 1992), and a new task that includes interaction with standard interface elements such as drop-down menus, sliders, and checkboxes. The test battery software captures pointing, tracking or dragging times, as well as the number and types of errors.…”