An Alternative to Measuring Subjective Workload: Use of SWAT without the Card Sort

One major drawback in some applications of the Subjective Workload Assessment Technique (SWAT) is the time required to administer the card sort. There are alternative methods of forming a workload composite from the SWAT instrument (i.e., a simple sum of the three scales or composite derived from multivariate statistics) which do not require the card sort. The present study compared the sensitivity of these alternative SWAT composite measures with the typical SWAT conjoint scaling metric which requires the card sort. A two group study was conducted in which subjects engaged in a continuous recognition task under twelve levels of task difficulty. One group (Pre-Task), performed the card sort prior to engaging in the task whereas in the other group (Post-Task) completed the card sort subsequent to task performance. Results indicated that placement of the card sort did not affect the task ratings on the three dimensions of SWAT nor did it affect the relative sensitivity of the three workload composites. All three composite measures were found equally sensitive to the task demands. These results indicate that the SWAT instrument can be used to effectively measure workload without having to perform the card sort.