Simplified subjective workload assessment technique.

Although the subjective workload assessment technique (SWAT) has been widely used, it has two main problems: it is not very sensitive for low mental workloads and it requires a time-consuming card sorting pretask procedure. In this study are presented five variations of SWAT in an effort to overcome the limitations. Four of the variants used the continuous SWAT subscales while one used the discrete SWAT subscale. Fifteen subjects participated in the experiment. The scales were compared with the original SWAT scale in terms of sensitivity and pretask procedure completion time when performing arithmetic tasks. The results show that all four variants are more sensitive than the conventional SWAT scale and that the pairwise comparison procedure takes significantly less pretask completion time compared with the original SWAT scale. Thus, the conventional pretask procedure can be replaced by a simple unweighted averaging to yield a scale of high sensitivity.