Effect of Pairted Comparison Weighting and Weighting Context

Abstract

The present study compared three subjective workload measurement techniques—a unidimensional scale (UW) and two mutidimenional scales (TLX and ModSWAT)–using a continuous memory task. ModSWAT is a technique that uses the sum of the SWAT dimensions to form the workload composite rather than the standard conjoint measurement procedure. Both weighted and unweighted workload measures were obtained for the two multidimensional scales. The paired-comparison technique used by TLX was employed to weight the three SWAT dimensions. For both multidimensional scales, weighting context was also varied. Paired comparison of the workload dimensions was made either prior to the task in a general context or within context of the task just performed. The major findings were that: (1) ModSWAT and UW were more sensitive than TLX to the task demands (i.e., difficulty) of the continuous recognition task; (2) weighting context affected the weights that were assigned the workload dimensions for both TLX and ModSWAT; (3) weighting context did not affect the weighted workload scores; and (4) the weighted and unweighted workload composites were very similar. Results were interpreted within context of averaging across multiple dimensions when several dimensions are insensitive to the task demands. Variability in the weights assigned contributed to the failure to find a effect of weighting.