ABSTRACT
Workload has been defined as a set of task demands, as effort, and as activity or accomplishment (Gartner and Murphy 1979). The task demands (task load) are the goals to be achieved: the time allowed to perform the task, and the performance level to which the task is to be completed. The factors affecting the effort expended are the information and equipment provided the task environment, the subject’s skills and experience, the strategies adopted, and the emotional response to the situation. These definitions provide a testable link between task load and workload. For example (paraphrased from an example given by Azad Madni, Vice President, Perceptronics, Woodland Hills, California, on results of an army study), the workload of a helicopter pilot in maintaining a constant hover may be 70 on a scale of 0 to 100. Given the task of maintaining a constant hover and targeting a tank, workload may again be 70. The discrepancy results from the pilot imposing a strict performance requirement on hover-only (no horizontal or vertical movement), but relaxing the performance requirement on hover (movement of a few feet) when targeting the tank to keep workload within a management level. These definitions enable task load and workload to be explained in real-world situations. These definitions also enable logically correct analysis of task load and workload.
