effects of interface design upon user productivity
Eight subjects experienced in the use of both 7000 and 11000 series oscilloscopes performed four typical tasks with each scope. The 7000 interface is a dedicated physical control system, while the 11000 system employs icons, pop-up menus, assignable controls, and a touch panel. On each trial the task time and measurement accuracy were recorded. Each experimental session was video recorded and verbal protocols were collected. These allowed decomposition of the subjects' behaviors into categories that would account for performance differences between the two scopes. A 77\% performance difference is explained in terms of the cognitive factors of strategy selections and recall of operational details.
effect interfaces interface design use user product performance task physical control control systems systems assignment touch timing measurement accuracy experimentation video decomposition behavior account cognition factor strategies select