Strain, P. S., & Bovey, E. H. (2011). Randomized, controlled trial of the LEAP model of early intervention for young children with autism spectrum disorders. Topics in Early Childhood Special Education, 31(3), 133–54. https://doi.org/10.1177/0271121411408740 

Type of Study: Randomized controlled trial
Number of Participants: 524 (56 preschool classrooms)

Population:

• Age — Not specified
• Race/Ethnicity — Not specified
• Gender — Not specified
• Status — Participants were individuals who met criteria for autism spectrum disorder (ASD) and teachers.

Location/Institution: Not specified

Summary: (To include basic study design, measures, results, and notable limitations)
The purpose of the study was to provide a description of an approach to individualize group instruction and an evaluation of pre-academic/academic program effects for normally developing and autistic-like children. Participants were Twenty-three inclusive preschool classrooms (that were randomly assigned to receive two years of training and coaching to fidelity in the LEAP (Learning Experiences and Alternative Program for Preschoolers and Their Parents) preschool model [now called LEAP Preschool], and 28 inclusive classes that were assigned to receive intervention manuals only. Measures utilized include the Childhood Autism Rating Scale (CARS), the Mullen Scales of Early Learning, the Preschool Language Scale (4th ed.; PLS-4), the Social Skills Rating System (SSRS), and a social validity measure. Results indicate that after two years, experimental class (fully implemented LEAP) children were found to have made significantly greater improvement than their comparison cohorts on measures of cognitive, language, social and problem behavior, and autism symptoms. Behavior at entry did not predict outcome, nor did family socioeconomic status. The fidelity with which teachers implemented LEAP strategies did predict outcomes. Finally, social validity measurement showed that procedures and outcomes were favorably viewed by fully implemented LEAP class teachers. Limitations include compromises in child assessment methods were made by not using direct observational measures of child behavior related to autism symptoms, communication skills, and social behaviors; and conducting the RCT in “authentic” settings imposed limitations on the child participants and related diagnostic information, specifically, did not have independent, confirmatory diagnoses of autism.

Length of controlled postintervention follow-up: None.

Boyd, B. A., Hume, K., McBee, M. T., Alessandri, M., Gutierrez, A., Johnson, L., Sperry, L., & Odom, S. L. (2014). Comparative efficacy of LEAP, TEACCH, and non-model-specific special education programs for preschoolers with autism spectrum disorders. Journal of Autism and Developmental Disorders, 44(2), 366–380. https://doi.org/10.1007/s10803-013-1877-9

Type of Study: Pretest–posttest study with a nonequivalent control group (Quasi-experimental)
Number of Participants: 273 (75 teachers and198 children)

Population:

• Age — Not specified
• Race/Ethnicity — Teachers: 72 White and 3 Black; Children: 92 White, 69 Hispanic, 23 Black, 10 Asian, and 4 Not Specified
• Gender — Teachers: 74 Female and 1 Male; Children: 165 Male and 33 Female
• Status — Participants were individuals who met the criteria for autism spectrum disorder (ASD) and preschool teachers.

Location/Institution: Florida, Colorado, and Minnesota

Summary: (To include basic study design, measures, results, and notable limitations)
The purpose of the study was to compare LEAP (Learning Experiences and Alternative Program for Preschoolers and Their Parents) [now called LEAP Preschool] and TEACCH classrooms to each other and a control condition in which teachers in high-quality special education programs used non-model-specific (NMS) practices. Participants were either in LEAP, TEACCH, or NMS classrooms. Measures utilized include the Autism Diagnostic Observation Schedule (ADOS), the Childhood Autism Rating Scale, the Leiter International Performance Scale-Revised, the Mullen Scales of Early Learning, the Pictorial Infant Communication Scales, the Preschool Language Scales, 4th Edition, the Social Responsiveness Scale, the Repetitive Behavior Scales-Revised, the Vineland Adaptive Behavior Scales, Survey Edition, and the Social Communication Questionnaire (SCQ). Results indicate that across conditions, children’s performances improved over time. Limitations include the study may not have been sufficiently powered to detect differences between three active treatment conditions, the crossover of classroom practices, and the lack of follow-up.

Length of controlled postintervention follow-up: None.

Strain, P. S. (2017). Four-year follow-up of children in the LEAP randomized trial: Some planned and accidental findings. Topics in Early Childhood Special Education, 37(2), 121–126. https://doi.org/10.1177/0271121417711531

Type of Study: Randomized controlled trial
Number of Participants: 524 (56 preschool classrooms)

Population:

• Age — Not specified
• Race/Ethnicity — Not specified
• Gender — Not specified
• Status — Participants were individuals who met criteria for autism spectrum disorders (ASD).

Location/Institution: Not specified

Summary: (To include basic study design, measures, results, and notable limitations)
The study used the same sample as Strain et al. (2011). The purpose of the study was to report on a 4-year follow-up study from the Learning Experiences and Alternative Program for Preschoolers and Their Parents (LEAP) [now called LEAP Preschool] randomized trial of early intervention for young children with autism. Participants were from twenty-three inclusive preschool classrooms that were randomly assigned to receive two years of training and coaching to fidelity in the LEAP preschool model, and 28 inclusive classes that were assigned to receive intervention manuals only. Measures utilized include the Childhood Autism Rating Scale (CARS), the Mullen Scales of Early Learning, the Preschool Language Scale (4th ed.; PLS-4), the Social Skills Rating System (SSRS), and a social validity measure. Results indicate that participants from LEAP classes were marginally superior to comparison class children on elementary school outcomes specific to communication, adaptive behavior, social, academic, and cognitive skills. Statistically significant group differences were noted in cognitive development and social skills. However, when placement was treated as an independent variable, very large effects were seen across all outcome measures, including autism symptoms, for children who were enrolled in inclusive settings. Data from adult family members confirmed important changes in perceived quality of life. Limitations include the need for replication with more functional observational measures of children behaving in authentic settings, the need for replication with better measures of curricular variables and follow-up dosage of instruction, the need for replication with direct observational measures of teacher-child interaction, and the need for replication across diverse groups of children.

Length of controlled postintervention follow-up: None.