Detailed quantitative and computer models of human operators performing real world tasks are not easily developed. This paper proposes a technique that facilitates that development. It is posited that when a cognitive task analysis has been conducted, a computer simulation model useful for approximations of task completion time is often within reach. An activity network or order-of-processing diagram must first be constructed from the task analysis. Next, activity durations are found in the literature or approximated through multidimensional scaling. Lastly, equations are written for calculating task completion time, or a program is written for simulations to estimate the time. Resulting models can be useful for optimizing system design. The approach is illustrated with an activity network by W.D. Gray et al. (1993) for a telephone operator task. Simulations demonstrate the feasibility of using multidimensional scaling to obtain approximate activity durations. The approach is also illustrated with an order-of-processing diagram representing drivers reading roadside message displays.
Samenvatting