Assessing the Validity of SWAT as a Workload Measurement Instrument

Abstract

The Subjective Workload Asssessment Technique (SWAT) carries with it the implicit assumption that people can accurately predict the amount of mental workload they would experience under various levels of three component dimensions. Research suggests that the perceptions of these dimensions may not be independent. This study was designed to measure the subjective interactions between the dimensions used in SKAT. Mental workload was generated using a text editing task in which the dimensions were manipulated independently. Results revealed significant positive correlations between the subjective levels of the three dimensions. That is, when a subject experienced a high level of one dimension, s/he also tended to rate the other two dimensions high. It may be unreasonable to assume that people can accurately predict the magnitude of these interactions when performing the ranking process which is used to derive the workload scale.

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References

Boyd

S. P.

The use of conjoint analysis in the interval subjective scaling of mental workload. Proceedings of the Eighth Psychology in the Department of Defense Symposium. Colorado Springs: USAF Academy, April 1982.

Creelman

C. D.

Human discrimination of auditory duration. Journal of the Acoustic Society of America. 1962, 34, 582–593

Hart

S. G.

Childress

M. E.

Hauser

J. R.

Individual definitons of the term “workload.”

Proceedings of the Eighth Psychology in the Department of Defense Symposium. Colorado Springs: USAF Academy, April 1982.

Michon

J. A.

Processing of temporal information and the cognitive theory of time experience. In Fraser

J. T.

Haber

F. C.

Muller

G. H.

(Eds.) The study of time. Heidelberg: Springer, 1972.

Orstein

R. E.

On the experience of time. London: Penguin, 1969.

Reid

G. B.

Eggemeier

F. T.

Nygren

T. E.

An individual differences approach to SWAT scale development. Proceedings of the Human Factors Society 26th Annual Meeting. Seattle: Human Factors Society, 1982.

Reid

G. B.

Shingledecker

C. A.

Eggemeier

F. T.

Application of conjoint measurement to workload scale development. Proceedings of the 25th Annual Meeting of the Human Factors Society. Rochester: Human Factors Scoiety, 1981.

Sheridan

T. B.

Simpson

R. W.

Toward the defintion and measurement of the mental workload of transport pilots. Cambridge: Massachusetts Institute of Technology, Contract No. DOT-OS-70055, January, 1979.