Aim: The aims of the study were to: (1) build new item banks for a revised version of the Pediatric Evaluation of Disability Inventory (PEDI) with four content domains: daily activities, mobility, social/cognitive, and responsibility; and (2) use post-hoc simulations based on the combined normative and disability calibration samples to assess the accuracy and precision of the PEDI computer-adaptive tests (PEDI-CAT) compared with the administration of all items. Method: Parents of typically developing children (n = 2205) and parents of children and adolescents with disabilities (n = 703) between the ages of 0 and 21 years, stratified by age and sex, participated by responding to PEDI-CAT surveys through an existing Internet opt-in survey panel in the USA and by computer tablets in clinical sites. Results: Confirmatory factor analyses supported four unidimensional content domains. Scores using the real data post hoc demonstrated excellent accuracy (intraclass correlation coefficients greater than or equal to 0.95) with the full item banks. Simulations using item parameter estimates demonstrated relatively small bias in the 10-item and 15-item CAT versions; error was generally higher at the scale extremes. Interpretation: These results suggest the PEDI-CAT can be an accurate and precise assessment of children's daily performance at all functional levels.