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Introduction: General population job-exposure matrices (JEMs) based on expert assessments of physical exposures may be valuable tools for studying occupation-related musculoskeletal disorders. Wrist-hand JEMs are few and the reliability and validity of expert assessments of wrist-hand exposures is uncertain.

Methods: We examined intra- and inter-rater reliability of ratings of five experts of hand-wrist repetition, deviation, force, vibration, and computer work in 33 jobs selected to represent a large exposure variation. The validity of ratings of hand-wrist repetition was examined by comparison with electro-goniometer measurements of wrist angular velocity and mean power frequency (MPF), and the validity of hand-wrist deviation by comparison with goniometer measurements.

Results: Intra-rater test-retest and inter-rater Spearman correlation coefficients controlling for rater effects, varied between 0.70 and 0.87. Corresponding kappa statistics of overall agreement showed similar high values, except for wrist deviation (kappa=0.50). Regression analyses showed strong positive associations between expert assessments of repetition and goniometer measurements of wrist angular velocity (R2=0.56, p<0.0001) and MPF (R2=0.37, p<0.0003), while expert ratings of wrist deviation showed a weak statistically nonsignificant association with goniometer measurements of ROM (R2=0.032, p=0.34).

Discussion: The main limitations were lack of objective measurements of required hand force, exposure to vibration, and computer work. Another limitation is exposure heterogeneity within exposure categories. For example, force may be dynamic or static, and computer work may be predominantly mouse or keyboard work. The results may not be generalized to other settings and assessments of hand-wrist exposures by other experts.

Conclusion: The reliability of expert assessments of wrist-hand physical exposures was high. Compared to goniometer measures, the validity of assessments of wrist-hand repetition was also high, but it was low for assessments of wrist-hand deviation. The results are encouraging for establishing a hand-wrist JEM, but the results for wrist deviation emphasize that expert assessments should be validated against objective measurements.