Workload Assessment of a Mobile Air Defense Missile System

Abstract

Four operator workload (OWL) scales were retrospectively applied to crewmembers of a mobile air defense missile system, LOS-F(H), following a candidate-selection field evaluation: NASA TLX, SWAT, Overall Workload (OW), and the Modified Cooper-Harper (MCH). Jackknife factor analysis revealed the presence of only a single factor (explaining 79.6% of the total variation) and indicated a significant (p<.0075) ordering of the mean factor loadings: TLX (.935) and OW (.927) were significantly greater than MCH (.862) and SWAT(.860). Comparison with an earlier field test of a remotely piloted vehicle revealed a significant (p<.00005) interaction of test and ordering of the OWL scales, but TLX and MCH consistently had the respectively highest and lowest loadings across the two field tests. Multiple correlation also revealed a significant (p < .0001) relationship, R = 0.66, between system performance and TLX. These findings and lessons learned are discussed in the context of the development and validation of a methodology for assessing OWL.

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