Cross-cultural validity of a naturalistic observational assessment of children's hand skills: a study using Rasch analysis.

OBJECTIVE To investigate cross-cultural validity of a newly developed Assessment of Children's Hand Skills (ACHS) in children with and without disabilities. SUBJECTS One group of 138 Australian children and 134 Taiwanese children, age range 2-12 years (a total of 149 typically developing children and 123 children with disabilities). METHODS Rasch model analysis was used to evaluate rating scale performance, person-fit, and item unidimensionality of pooled data from the ACHS. Rasch-based differential item functioning was used to evaluate differences in item difficulties between cultural groups. RESULTS The appropriateness of the ACHS 6-level rating scale was confirmed in the pooled analysis. All 22 activity items and 19 of 20 hand skill items in the ACHS formed a unidimensional scale. The ACHS exhibited reasonable response patterns when applied to the composite sample of Australian and Taiwanese children. Differential item functioning was found in 7 activity items and 7 hand skill items. CONCLUSION The ACHS can be used to assess and compare children's hand skills across Australian and Taiwanese cultural contexts with confidence. Adjustment for differential item functioning may be used when pooling or comparing ACHS data from these cultural groups.