According to the Centers for Disease Control, autism is increasingly becoming a public health crisis with a prevalence that has reached 1 in 110. To provide early intervention, LEAP–USA was developed as a comprehensive intervention model for preschool children with autism. Based on inclusion with typically developing peers, it aims to provide intervention and early education for young children with autism in a manner that does not tax school systems' limited resources. The first randomized controlled trial (RCT) of LEAP has recently been completed, comparing the full-scale model with training to a reduced one. The evaluation demonstrated positive impacts in the areas of child cognition, language, social skills, and symptom severity. The purpose of the current project is to follow these same children who participated in the original RCT over the next three years. The researchers will examine whether: a) the gains demonstrated in the previous evaluation continue to manifest themselves; b) positive impacts are found in additional areas (classroom placement, academic achievement, use of supportive services); and c) contemporaneous classroom quality is related to student outcomes. The researchers will recruit the children who participated in the classrooms of the original RCT. Data on child developmental outcomes (direct assessments, teacher rating scale) will be collected longitudinally at the start of the study and at the end of each of the three school years. Data on child outcomes in the educational system (classification, classroom placement, services received) will also be obtained annually. Observational data on classroom quality will be collected three times each school year. Products from this project will include published reports and presentations on the efficacy of the LEAP intervention for preschoolers with autism over time through early elementary school.