The Effects of Early Intervention on Social Communication Outcomes for Children with Autism Spectrum Disorder: A Meta-analysis.

Many studies did not use or report blind assessors, and many did not use intent to treat analysis. Most studies used dyadic outcome measures tied to the treatment context, so gains may not generalize to untrained partners or settings. The included studies varied widely in intervention type, dosage, participants, and measures, and a moderate amount of heterogeneity remained unexplained. Dosage was difficult to estimate because many studies reported training time for parents or school staff rather than actual intervention time with the child. The age finding came from study level mean age rather than individual child data, so the optimal age of 3.81 years should be treated cautiously. Only four studies examined school staff implemented interventions, and those children were older than children in other interventionist groups.

Do not read the overall effect size of g = 0.355 as proof that gains will generalize outside the treatment setting. Generalized measures showed a smaller effect of g = 0.234.