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 permitted 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 participant’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, CA, on the 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 also be 70. The discrepancy results from the pilot self-imposing a strict performance requirement on hover-only (no horizontal or vertical movement) but relaxing the performance requirement on hover (a few feet movement) when targeting the tank to keep workload within a manageable level. These definitions enable task load and workload to be explainable in real work situations. These definitions also enable a logically correct analysis of task load and workload.