Abstract
Background: Interest in the support needs of people with intellectual disability has directed attention to developing assessments to measure of the pattern and intensity of supports which people need to participate in valued life activities. Assessments of the support needs of children must account for the influence of age. Method: Four hundred fifty (450) Spanish children with intellectual disability (ages 5-16) were assessed with the SIS-C Spanish. To test for measurement invariance and latent differences, the SIS-C Spanish standardization sample was linked to the SIS-C English normative sample. Models developed during the norming process were used to investigate measurement equivalence across age groups, differences in latent means, and differences in latent variances and standard deviations. Results: Findings suggested that all items on the SIS-C Spanish could reliably be used to measure support needs of children ages 5-16. When exploring age-related differences at the latent level, however, data showed latent mean differences in support need domain scores across age cohorts. Conclusions: The same set of items can be used to measure support needs in children ages 5-16, but age-related influences must be considered in developing norms for the SIS-C Spanish as well as in planning supports for children.