Abstract
The Rapid Office Strain Assessment (ROSA) was developed to assess musculoskeletal disorder (MSD) risk factors for computer workstations. This study examined the validity and reliability of remotely conducted, photo-based assessments using ROSA. Twenty-three office workstations were assessed on-site by an ergonomist, and 5 photos were obtained. Photo-based assessments were conducted by three ergonomists. The sensitivity and specificity of the photo-based assessors' ability to correctly classify workstations was 79% and 55%, respectively. The moderate specificity associated with false positive errors committed by the assessors could lead to unnecessary costs to the employer. Error between on-site and photo-based final scores was a considerable ∼2 points on the 10-point ROSA scale (RMSE = 2.3), with a moderate relationship (ρ = 0.33). Interrater reliability ranged from fairly good to excellent (ICC = 0.667–0.856) and was comparable to previous results. Sources of error include the parallax effect, poor estimations of small joint (e.g. hand/wrist) angles, and boundary errors in postural binning. While this method demonstrated potential validity, further improvements should be made with respect to photo-collection and other protocols for remotely-based ROSA assessments.
1. Introduction
Recent developments in information technology have resulted in dramatic increases in occupational computer use (Blatter and Bongers, 2002). In 2000, approximately 60% of Canadian workers reported computer usage as part of their job duties, while 82% of those workers reported daily occupational computer use (Lin and Popovic, 2003; Marshall, 2001). In the United States, 2003 census data showed that over 50% and 60% of all employedmen and women, respectively, used a computer as part of their job (Day et al., 2005). This trend of increasing workplace computer use has been associated with an increase in work-related musculoskeletal disorders (WMSDs) and symptoms among workers (Mani and Gerr, 2000). Meta-analyses (Gerr et al., 2006; IJmker et al., 2007) found an overall positive association between computer usage and WMSDs.
5. Conclusions
The purpose of our study was to evaluate the validity and reliability of ROSA office workstation ergonomic assessments performed remotely using a series of photographs. The photo-based assessment results were compared the results of on-site assessments. The functional classification results indicated potential validity of the tested method, but showed that misclassifications could create undue costs to employers. Meanwhile, RMSE results and moderate correlation results showed that there is room for improvement in the accuracy of photo-based scoring. On a positive note, fairly good to excellent interrater reliability values showed that there was adequate consistency between photo-based raters when required to perform these remote, photo-based, assessments.
