VALIDATION OF OCCUPATIONAL HAND USE CATEGORIES

As part of a study of the etiology of carpal tunnel syndrome in indust ry, we developed a measure of occupational hand use activities, ''Occu pational Hand Use'' (OHU), using 471 workers from four industries. Thi s categorization has five categories based primarily upon observed rel ative force and secondarily upon observed relative repetitions. Becaus e the validity of this OHU categorization has been questioned, we devi sed a study to validate this variable by demonstrating its reliability . Using discriminant analysis, we show that the OHU categorization acc urately reflects the subjective impressions of other industrial worker s (605 workers from four other industries in the United States and Jap an). Within each validation industry, 68 to 88% of all workers were cl assified precisely to the correct OHU category, and an additional 10 t o 25% were classified to within one OHU category, for a hit or near-mi ss rate of 87 to 98%. The major classification error was due to some w orkers overestimating the repetitiousness of their jobs. An equation f or calculating OHU from subjective or objective data is provided.