Anticipating workload: Which facets of task difficulty are easiest to predict?

Prospective workload measures are used to assess individuals' expectations about tasks they are facing, how difficult they think the tasks will be and how well they expect to perform. In this study, 43 participants used the NASA-TLX subjective workload scale to predict the difficulty of surgical training tasks. The goal of the study was to determine the accuracy of their predictions and whether the act of assessing tasks before performing them affected their judgments post-perforrnance. Regarding initial performance, results showed that participants formed prospective judgments that were consistent with their retrospective judgments, but they underestimated physical demands. After only minimal practice, however, their retrospective judgments deviated from both the experimental group's initial predictions and the control group's initial retrospective assessments. Anticipating mental demand was particularly challenging. No significant differences were found between the control and experimental conditions for post-performance assessments, suggesting that pre-performance assessment of workload has no effect of post-performance judgment of task difficulty.