Reliability, Validity and Usability of Assessment of Functioning Tools for Autism

The National Disability Insurance Scheme (NDIS) is a major reform of the Australian disability sector that provides individuals with support costs based on the level of their functional impairment. Children diagnosed with autism spectrum disorder (ASD) make up a significant portion of paediatric clients accessing the scheme. However, the level of need differs markedly between individuals, ranging from individuals who have significant and lifelong support needs to those who may only require minimal support.

Currently, the most commonly used tool by the NDIS is the Pediatric Evaluation of Disability Inventory‐Computer Adaptive Test (PEDI‐CAT). Concerns have been raised from within the scientific literature, and through Australian community consultations, that this tool may inadequately define functional impairment in children on the spectrum. A modified version of the PEDI‐CAT for children on the spectrum has been created, termed the PEDI‐CAT (ASD). This tool shows significant promise, but must first be validated within the Australian context.

This project was funded by the National Disability Insurance Agency and aimed to:

1. Determine if the PEDI‐CAT (ASD) has acceptable validity (does the test measure what it aims to measure?) and reliability (are test results consistent?) for measuring functional ability in individuals aged 20 years or younger on the autism spectrum or with a related developmental condition who are engaging with the NDIS in Australia.
2. Determine if the PEDI‐CAT (ASD) has acceptable usability for measuring functional ability in individuals aged 20 years or younger on the autism spectrum or with a related developmental delay/condition from the perspectives of:
   1. parents/caregivers of children with these conditions; and
   2. clinicians who undertake clinical assessments for these conditions.