Development and Further Content Validation of the Motivation Assessment Tool for Physical Activity (MATPA) Among Children with Autism Spectrum Disorder.

This study describes the content validity process, focusing on children, to create and validate a tool for assessing motivation toward out-of-school physical activity (PA) among children with autism spectrum disorder (ASD) aged 6 to 17 years. Additionally, it establishes the eligible verbal communication age range necessary for its application. The initial development and content validity process with external experts is described elsewhere (An et al., 2025 under review). The MAT-PA was iteratively refined during the content validity process with twenty children (two with version 0.1, ten with version 0.2, and eight with version 0.3). Modifications were made based on feedback from children who completed the entire interview. The Vineland Adaptive Behavior Scales, Second Edition (VABS-2), assessed the age-equivalent for daily verbal communication skills required for the MAT-PA. Feedback from the twelve children who completed the entire interview process (two with version 0.1, six with version 0.2, and four with version 0.3) provided evidence supporting the tool's content validity. Challenges with attention spans and verbal abilities limited full participation from the remaining eight children. Parent-reported VABS-2 scores indicated that the MAT-PA is suitable for children with ASD who have verbal communication skills equivalent to 3-year-olds (receptive) and 6-year-olds (expressive). The MAT-PA is the first tool specifically designed to explore the psychological needs and behavioral regulation of children with ASD, providing evidence of content validity. Future work should focus on improving the tool's reliability for trial integration, exploring its applicability across diverse contexts, and leveraging technology to boost scalability and impact.