Findings  Data from 144 studies of early childhood autism interventions featuring 9038 children gathered in a prior systematic review and meta-analysis were analyzed to determine whether the effects of common interventions were associated with any of 3 indices of intervention amount (ie, daily intensity, duration, cumulative intensity). None of the models evidenced a significant association between intervention amount and intervention effects.

Meaning  There is not robust evidence that the benefits of early childhood interventions to young autistic children increase when those interventions are intensified; practitioners recommending interventions should consider what amounts would be developmentally appropriate.