Validity of occupational stress assessment using a visual analogue scale

Abstract

Background: The visual analogue scale (VAS) is empirically used by occupational physicians to assess stress but very few studies have been published about its quantitative validation. Aims: To assess the external validity of the VAS for the assessment of stress in the clinical occupational health setting by comparing its scores with the Perceived Stress Scale (PSS) of Cohen. Methods: An anonymous self-completed questionnaire (PSS14) and the VAS were filled in by a random sample of 360 workers from several occupational health centres. Results: No difference between the mean scores of PSS14 and stress VAS was found. The equation of the linear regression was 'VAS score = -0.18 + 1008 × PSS14 score'. A VAS score of 7.0 was identified as having the best sensitivity/specificity ratio (0.74 and 0.93, respectively) for identifying those with 'high stress' using the PSS cut-off score of 7.2, using a receiver operator curve approach. Conclusions: Our results support an acceptable agreement between the two tests, meaning that the two tools assess the same psychological construct. The good sensitivity/specificity ratio and the area under the curve close to 1 provide evidence that a VAS is suitable to help the occupational physician detect a high level of stress. The use of a VAS for stress assessment seems to be meaningful, suitable and useful for occupational physicians. © The Author 2011. Published by Oxford University Press on behalf of the Society of Occupational Medicine. All rights reserved.