Paper: Assessments in computer workers: A comparison of methods

Author(s) and Affiliation(s):
Trevor King, Institute for Work & Health
Dwayne Van Eerd, Institute for Work & Health, Applied Health Sciences Universtiy of Waterloo
Ivan Steenstra, Institute for Work & Health
Colette Severin, Institute for Work & Health
Donald C. Cole, Institute for Work & Health, Dalla Lana School of Public Health University of Toronto
Philip Bigelow, Institute for Work & Health, Applied Health Sciences Universtiy of Waterloo
Ben Amick III, Institute for Work & Health
Dorcas E. Beaton, Institute for Work & Health, St Michael’s Hospital Toronto
Day/Time: Saturday at 14:00
Room: St. Patrick Room, 3rd Floor
Objectives:

Our objective was to compare two non-intrusive and relatively inexpensive methods of computer exposure assessment: self-report (SR) and electronic monitoring (EM). EM software is widely used; however it results in (systematic) underestimation in exposure time when compared to self-report. Our intention was to examine these relationships at a closer level. A better understanding of these exposure measures will assist practitioners and decision-makers trying to assess and solve the source of computer worker pain/discomfort.

Methods:

SR data was collected using web-based questionnaires for 15 consecutive days; workers were asked to report daily use of mouse, keyboard, and computer. EM software recorded computer, keyboard, and mouse use. A commercially available mouse with a built-in transducer (www.hoverstop.com) recorded the time the hand was on or directly over the mouse. Continuous monitoring of the position of the computer user’s hand, relative to the mouse, gives a more accurate estimate of the time the user’s hand is on the mouse in a potential straining or static posture. Pearson correlations were used to compare exposure durations for computer, keyboarding, and mouse tasks. Study approval was obtained from the Research Ethics Board of the University of Toronto.

Results:

26 participants completed both SR and EM. SR and EM data were missing if subjects were absent from the office. SR data were also missing if subjects did not complete questionnaires. EM data were missing due to computer software conflicts. The Pearson correlation between SR and EM for computer use was r= 0.68, for keyboarding r=0.38, and mouse use r=0.54. The Pearson correlation between SR mouse and computer use was r=0.74, SR keyboard and computer use r=0.80, and SR mouse and keyboard use r=0.73. The Pearson correlation between EM mouse and computer use was r=0.95, EM keyboard and computer use r=0.66, and EM mouse and keyboard use r=0.40.

Conclusions:

There are moderate correlations between SR and EM methods for mouse use and computer use, and a lower correlation for keyboard use. The relatively consistent high correlation between tasks in the SR method might mean that subjects are not able to differentiate between mouse, keyboard, and computer use. The high correlation between computer use and mouse use in the EM method suggests that computer users’ hands are often in contact with the mouse. Self-report and activity monitoring may be measuring distinct constructs.