Comparison of self-reported and expert-observed physical activities at work in a general population

Concerns about exposure assessment quality have impeded research to identify risk factors for ergonomic disorders. We compared self‐reported and expert‐observed estimates of work‐related physical factors for participants in a study of carpal tunnel syndrome (CTS). We analyzed data from 61 subjects, including 28 CTS cases and 33 controls randomly sampled from a case‐control study with 417 participants. For 11 posture and manual materials handling factors, the median difference in mean exposure between self‐reported and expert‐observed exposure at work was less than 1/2 hour a day. Measurements by the two methods in this study agreed more often than expected by chance (median kappa 0.31 in cases and 0.28 in controls). Kappa differed significantly by case‐control status for two factors: bending at the waist (kappa 0.79 in cases versus 0.28 in controls, P = 0.01) and twisting of the forearm (kappa 0.45 in cases versus −0.02 in controls, P = 0.02). Although imperfect, exposure information collected from workers' self‐reports is useful for many ergonomic epidemiology studies. Am. J. Ind. Med. 34:29–35, 1998. © 1998 Wiley‐Liss, Inc.