Clinically Significant Outcomes of Early Intensive Behavioral Intervention for Children With Autism Spectrum Disorders: An Individual Participant Data Meta‐Analysis

ABSTRACT Early Intensive Behavioral Intervention (EIBI) is widely recommended for children with Autism Spectrum Disorder (ASD). However, the treatment intensity and effectiveness have been debated. We conducted a meta‐analysis and examined individual participant data to evaluate the effectiveness and clinical significance of the outcomes on adaptive behavior, intellectual functioning, and autism severity. We included studies of children with ASD aged 2–6 years who received EIBI for at least 12 months. The final literature search was conducted on September 26, 2024. The GRADE tool was used to assess the risk of bias. Across the 17 identified studies, we obtained participant data from 15 studies: 341 children received EIBI and 280 were in comparison‐groups. All studies had a serious risk of bias due to the lack of random assignment. Our meta‐analysis yielded effect sizes of 0.66 for improvement in adaptive behavior, 0.87 for improvement in intellectual functioning and 1.36 for reductions in ASD severity. A significantly higher percentage of children in the EIBI‐group met the criteria for statistically reliable change and scored in the non‐clinical range post‐intervention with a Number Needed to Treat between 4.1 and 6.9. We found that treatment intensity significantly contributed to changes across all outcome measures. Based on our analyses we propose benchmarks for evaluating interventions for children with ASD. Although EIBI demonstrates broad, substantial effects, some uncertainty remains due to the lack of random assignment in the reviewed studies. Nonetheless, EIBI should currently be considered as the preferred treatment for children with ASD.