Robust evidence supports the efficacy of early autism intervention. Despite broad consensus that earlier intervention leads to better outcomes, evidence for this has been limited to correlational studies. This study examined timing effects of the Early Social Interaction (ESI) model, a parent-implemented intervention, using a complete crossover…

In the United States, early intervention (EI) programs under Part C of the Individuals with Disabilities Education Act serve thousands of infants and toddlers with or at risk for developmental delays. Despite this, few studies have investigated the developmental progress and outcomes of children served, especially in relation to the heterogeneity…