Benefits of Using Objective and Subjective Workload Measures

Abstract

This paper describes the results of two measures of workload, one objective, one subjective, that were applied to a series of switch setting exercises. The objective measure was an Interval Production Task (IPT), based upon a secondary task paradigm, in which the subject is required to maintain a constant rate of tapping with one hand while performing the primary task with the other hand. According to the supporting theory, variations in workload on the primary task will be reflected in variations in the tapping rate. Previous studies have found the IPT to be particularly sensitive to changes in the psychomotor workload. The subjective measures used were the Subjective Workload Assessment Technique (SWAT). Although the two workload measures did not produce the same level of significance for workload differences, it should be noted that they did produce the same rank order for the three tasks. It was concluded that the use of both subjective and objective measures of workload could produce increased confidence in the results, as well as insight into the nature of the task loading.