How Screening and Diagnostic Tools Shape Autism Prevalence in School-Aged Children: A Bibliometric-Systematic Review (2015-2025).

Autism spectrum disorder (ASD) prevalence estimates vary widely across countries and over time, partly due to differences in the screening and diagnostic tools used. This study combined bibliometric analysis and systematic review methods to examine global publication trends and evaluate the use of standardized assessment tools in ASD prevalence studies involving school-aged children (typically 6-12 years). A bibliometric search of the Scopus database (2015-2025) identified 107 publications, which were analyzed for citation patterns, research themes, and geographic distribution. Of these, 18 studies met systematic review inclusion criteria, reporting ASD prevalence in the general population and high-risk samples across diverse regions. The most frequently used screening tools were the Social Communication Questionnaire (SCQ) and Childhood Autism Spectrum Test (CAST), while gold-standard diagnostic tools such as the Autism Diagnostic Observation Schedule (ADOS/ADOS-2) and Autism Diagnostic Interview-Revised (ADI-R) were common for diagnostic confirmation. However, psychometric performance and cultural adaptation processes varied, and many tools were not validated for the study population. Tool selection and adaptation were found to directly influence prevalence estimates, with implications for research comparability and policy planning. Findings highlight the need for culturally validated instruments, standardized sampling approaches, and increased representation of low- and middle-income countries in ASD prevalence research to ensure equitable and accurate identification.