Targeted-Tracking With Pointing Devices

Targeting and tracking in graphical user interfaces have been widely studied, but attempts to model targeted-tracking are few. Targeted-tracking is essentially a two component task of tracking followed by targeting, where either or both components may dominate depending on the levels of difficulty in each component. The applicability of an empirical model based on computer mouse use is unknown with respect to other devices. In order to confirm the model validity for other input devices, experiments were carried out using a mouse, a pen mouse, a touch screen, and a graphics tablet. Fourteen participants were tested on 48 experimental conditions that included four difficulty levels and 12 conditions with varying track width (P), track length (D), and target width (W). Movement time, error rate, index of performance, and throughput were compared. Repeated-measures ANOVA indicated that factors in the targeted-tracking model were significant (ρ <; 0.05) and movement time data were a good fit (R² > 0.8) to the model, confirming the generality of the model. A principal component analysis showed that a mouse is relatively superior in terms of both movement time and error rate. Thus, the targeted-tracking model is an effective way to compare and evaluate input devices.