Serious Game Aimed at Assessing Executive Planning Skills in Children With Autism: Cross-Sectional Design and Formative Evaluation of ShopAutiPlan.

Background: Planning deficits are a common and functionally significant executive function difficulty in children with autism, affecting everyday activities such as organizing tasks, prioritizing goals, and monitoring progress. Traditional neuropsychological assessments often lack ecological validity and may not capture these skills in real-world contexts. Serious games offer promising alternatives by simulating everyday scenarios and enabling observation of planning behaviors during interactive tasks. However, most existing systems focus on training rather than theory-driven assessment, and are rarely evaluated for usability before deployment with children with autism. Objective: This study aimed to design and evaluate ShopAutiPlan, a supermarket-based serious game intended to assess executive planning skills in children with ASD by conducting a formative expert evaluation before its use in clinical or research settings. The evaluation sought to identify usability strengths and limitations, ensuring that the system aligns with planning theory and accommodates the unique needs of autistic users. Methods: A theory-driven design approach grounded in the Hayes-Roth cognitive model of planning was used to map planning subcomponents-including goal formulation, strategy generation, sequencing, execution, and monitoring-to in-game tasks and logged behavioral metrics. A cross-sectional, formative expert-based usability evaluation was conducted using inspection and think-aloud protocols. Six domain experts (2 psychologists, 2 human-computer interaction researchers, and 2 game developers) participated in individual evaluation sessions. Usability assessment was guided by ASD-specific usability heuristics, and experts completed the System Usability Scale (SUS). SUS scores were summarized using descriptive statistics, and qualitative feedback was analyzed through deductive coding mapped to heuristic categories. Results: Across experts, 45 usability issues were identified, spanning cognitive accessibility, feedback clarity, realism, and technical performance. Severity ratings varied according to disciplinary perspectives: psychologists highlighted cognitive load, sensory accessibility, and task clarity, whereas developers focused on system responsiveness, interaction consistency, and technical reliability. The overall SUS score (mean 70.4, 95% CI 45.2-95.7) exceeded the standard benchmark of 68, supporting the acceptability of the system and complementing the qualitative findings from the heuristic evaluation. Recommendations from the evaluation informed iterative refinements to interface design, interaction flow, and task representation to enhance alignment between planning constructs and user experience. Conclusions: To the best of our knowledge, this study introduces the first shopping-based serious game specifically designed to assess executive planning skills in children with autism. Unlike many existing autism-related serious games that primarily focus on intervention or training, ShopAutiPlan adopts a theory-driven assessment-oriented design grounded in a cognitive model of planning and supported by gameplay-based behavioral measures. By integrating cognitive theory, serious game design, and interdisciplinary usability evaluation, the study proposes a structured framework for developing ecologically valid digital assessment tools that may complement conventional neuropsychological approaches in autism research and clinical practice.