Validating the language domain subtest in a developmental assessment scale for preschool children.

This study reports on the validation of the language domain subtest of a developmental assessment scale for Cantonese Chinese preschool children. Three hundred and seventy eight multi-stage randomly selected children between 3;4 and 6;3 years of age were tested on the 104-item subtest. Fifty-four of these children, spreading across three age groups, demonstrated developmental problems. Results from the Rasch analyses suggested that the original and the shortened 66-item version demonstrated adequate measurement properties, including targeting and uni-dimensionality. Statistical analyses of the shortened version suggested that the subtest demonstrated strong test-retest reliability, and adequate convergent and criterion validity. This study contributes to good practice in the development of standardized normative tests, particularly those for investigations of language problems in Chinese children given that reports on existing tests' psychometric properties were often incomplete.