Exploring the Effectiveness of Community-Based, Intensive Transdisciplinary Early Intervention for Autistic Children in Australia: An Observational Study of 577 Children

Emerging evidence suggests that community-based early intervention (EI) for autistic children results in lower gains than those observed in controlled research settings. To explore further, this observational study evaluated data from 577 children engaged in a large Australian community-based autism-specific EI service between 2014 and 2024. Children’s developmental quotient (DQ) was assessed at intake, annually and upon exit, and pre- and post-intervention differences in verbal, non-verbal and composite DQ were examined. Differences were also examined between children who transitioned out of the EI program within 12 months (Cohort 1) versus 24 months (Cohort 2). Results identified significant improvements in all DQ scores post-intervention, with those in Cohort 2 demonstrating greater improvement in verbal DQ and lower improvement in non-verbal DQ. Children in Cohort 2 were also more likely to be younger, diagnosed earlier, and have no prior intervention history and more pronounced autism characteristics. Limitations to these findings are discussed.