Evaluation of Three Methodologies for Assessing Work Activity During Computer Use

Abstract

The overall goal of this study was to evaluate three separate methodologies for gathering work activity information among computer users. These methodologies included worker self-report, work sampling, and activity monitoring. A repeated measures design was employed whereby data were collected simultaneously on each subject (n = 51) across three consecutive workdays. Exposure information gathered included keying time, mouse usage, and time spent performing various work tasks (i.e., writing, proofreading, handling documents). Subjects were recruited to represent a wide range of keyboard activity and mouse usage. The study found that worker self-reports overestimated actual keyboard usage by a factor of approximately 1.5 for workers using the keyboard an average of 4 hours per day to a factor of 4 for workers using the keyboard an average of 30 min per day. On average, there was an approximate twofold difference between worker self-reported keying time and that obtained via activity monitoring and work sampling. This trend was similar with regard to time spent using the computer mouse. Worker self-reported mouse usage was approximately twofold higher than that obtained via activity monitoring or work sampling. Self-reported exposure information not only resulted in different estimates, but showed greater variance compared with the other methodologies. The results of this study suggest that the use of worker self-reported exposure information on keying time and mouse usage may not represent an accurate account of time spent performing these tasks. In the context of epidemiological studies work sampling and/or activity monitoring would be more suitable methodologies for obtaining such information.

Risk factors for persistent elbow, forearm and hand pain among computer workers

“…This finding is in accordance with the results of other studies (15,16). However, there were no statistically significant effects of mouse and keyboard times on the prognosis of arm pain, whether self-reported or objectively recorded.…”

Does computer use pose an occupational hazard for forearm pain; from the NUDATA study

“…In a recent experimental study, self reported mouse and keyboard times were shown to be 2-3 times lower than objectively measured. 13 However, the rank correlations between self reported times and objective times were 0.71 and 0.78 for mouse and keyboard times, respectively, when self reports were made at the end of the same day as the measurements were made. In real life, including retrospective assessment over longer periods, for example, four weeks, as used in the present study, these correlations may well be lower.…”

Test–retest reliability and validity of self-reported duration of computer use at work

“…Homan & Armstrong (2) reported less overestimation among workers with longer durations of computer use (according to work sampling) than among workers with shorter durations of computer use. These observations seem to be in contradiction.…”

“…Previous studies have shown that computer workers generally overestimate their duration of computer use at work (2)(3)(4)(5). In epidemiologic studies, the overestimation by individual participants leads to the misclassification of exposure (ie, exposure values that are too high are assigned to participants).…”

“…However, insufficient information is available regarding the reliability and validity of the questionnaires used in these studies (1). This lack of information may hamper the determination of a potential threshold dose (ie, number of hours of computer use at work) that may be relevant in the prevention of musculoskeletal symptoms and disorders at work (2).…”