Preliminary Reliability and Validity of the M-CHAT-S, a New Autism Screening Tool for School-Aged Children

Identifying autism early is critical for ensuring timely access to appropriate educational and clinical supports. Current autism screening practices primarily focus on toddlers; universal practices for identifying the substantial portion of autistic children who arrive at school age without a diagnosis are lacking. This study evaluates the preliminary reliability and validity of the Modified Checklist for Autism in Toddlers-School Age version (M-CHAT-S), a novel screener designed for early school-age children, with separate versions for verbally fluent and minimally verbal children. A total of 165 caregivers and 107 educators completed the M-CHAT-S, along with the Social Responsiveness Scale, Second Edition (SRS-2), to test convergent validity, and the Child Behavior Checklist (CBCL), to test discriminant validity. Findings demonstrate strong internal consistency across versions (Cronbach's α = .79-.92) and robust construct validity. Children with preexisting autism diagnoses scored higher on the M-CHAT-S than nonautistic children. Both test-retest reliability and interrater reliability were in the moderate range. Despite these limitations, the M-CHAT-S demonstrates promise as a screening tool that could facilitate earlier identification of autistic children in school settings. Future research will involve a partnership with school districts to support school-based validation and implementation.Lay AbstractChildren with disabilities have a right to a free and appropriate public education in the United States. Children who are not identified by the time of school entry are likely to miss out on appropriate services and supports to which they would otherwise be legally entitled. Many studies show that a large portion of individuals who are ultimately diagnosed with autism are not identified until by the time they start school.Screening tools can help identify children who may be on the autism spectrum. Universal autism screening is currently recommended for toddlers, but not school-age children. To address this gap, we developed the Modified Checklist for Autism in Toddlers-School Age version (M-CHAT-S) for children in early elementary school. This study tested the consistency and accuracy of the M-CHAT-S for both verbally fluent and minimally verbal children.We asked 165 caregivers and 107 educators to complete the M-CHAT-S and compared their responses to other well-established measures of autism traits and behavior. Overall, we found that the M-CHAT-S had good reliability, meaning that the items in the measure were consistent with each other. Children with a known autism diagnosis scored higher on the M-CHAT-S than non-autistic children. M-CHAT-S scores were more strongly related to another autism screening tool (the SRS-2) than to a survey of general behavior (the CBCL). However, test-retest reliability (whether the same rater's score stayed consistent over time) and interrater reliability (whether two different raters agreed on scores) were lower than expected.These results suggest that the M-CHAT-S may be a useful tool for identifying autistic children in early school years. Future research will involve partnering with school districts to be able to reach as many children as possible, including autistic children who have not yet been identified. If validated further, this tool could help schools and families recognize children who need autistic support, leading to earlier access to services.