Clinical Research Directory

Inclusion Criteria: * Diagnosis of Autism Spectrum Disorder (ASD) based on clinical interview and Diagnostic and Statistical Manual, 5th edition (DSM-5) and confirmed using the Autism Diagnostic Interview Revised (ADI-R) and Autism Diagnostic Observation Schedule, 2nd edition (ADOS-2) or Childhood Autism Rating Scale (CARS-2); Diagnostic and Statistical Manual, 5th edition (DSM-5), and expert clinical opinion * Boys and girls between 2 years and 3 years and 11 months * Ability to participate in the testing procedures to the extent that valid standard scores can be obtained * Stable treatment (e.g., applied behavior analysis (ABA), speech therapy, psychotropic medication(s) or biomedical intervention(s) for at least 1 month prior to baseline measurements with no anticipated changes during study participation * Developmentally delayed with Mullen Scales of Early Learning (MSEL) or Developmental Profile (DP-4) composite score below 85 (1 Standard Deviation below the mean) * Availability of at least one English-speaking parent who can consistently participate in parent training and research measures. Exclusion Criteria: * Current or lifetime diagnosis of severe psychiatric disorder (e.g., bipolar disorder, etc.) * Presence of active medical problem (e.g., unstable seizure disorder or heart disease) * Child primary language other than English * Previous adequate trial of Pivotal Response Treatment * More than 15 hours per week of in-home applied behavior analysis (ABA).