Development of a school-age extension of the Modified Checklist for Autism in Toddlers through expert consensus and stakeholder input
Authors: Wieckowski Andrea Trubanova , Perez Liz Georgina , de Marchena Ashley , Fein Deborah A , Barton Marianne L , Vivanti Giacomo , Robins Diana L 
Published: May 2024

Universal autism screening is recommended by the American Academy of Pediatrics at 18 and 24 months. However, many children are not identified until after the age of 4 years, and some not until adulthood, either due to mild or no indication of symptoms early in development, or to co-occurring conditions which may overshadow autism symptoms. This indicates a need for universal autism screening measures for school-age children. This project adapts the widely used toddler autism screening tool, the Modified Checklist for Autism in Toddlers, Revised, with Follow-Up (M-CHAT-R/F), for use in school-age children, called M-CHAT-School (M-CHAT-S). The study follows the Patient-Reported Outcomes Measurement Information System guidelines for measure development to create parent- and teacher-report versions of the M-CHAT-S for 4- to 8-year-old children. Through expert consensus feedback via a Delphi pool and cognitive interviewing with stakeholders (i.e. parents and teachers), we developed two versions of the M-CHAT-S to be used for verbal and minimally verbal children. The M-CHAT-S poses several advantages to existing measures, including brevity, items updated based on current knowledge and conventions, and narrow age range to assure items are developmentally appropriate. Future steps include validation of the M-CHAT-S to determine its utility as an autism screener for young school-age children. Lay abstract The American Academy of Pediatrics recommends universal screening to identify children at higher likelihood for autism at 18- and 24-month well-child visits. There are many children, however, that are missed during this toddler age who do not get diagnosed until much later in development, delaying access to autism-specific interventions. Currently, brief measures for universal autism screening for school-age children, however, are lacking. In this project, we adapted a commonly used autism screener for toddlers, the Modified Checklist for Autism in Toddlers, Revised, with Follow-Up (M-CHAT-R/F), to be used for school-age children. This measure, called the M-CHAT-School (M-CHAT-S), is a parent- and teacher-report questionnaire to be used to screen for autism in school-age children aged 4 to 8 years of age. M-CHAT-S was developed through feedback from autism experts, as well as interviews with parents and teachers to provide input on the items. Two versions of M-CHAT-S were developed, one for verbally fluent and one for minimally verbal school-age children. M-CHAT-S is a brief measure, with updated items to reflect changes in the way experts think and talk about autism, making it a useful measure to use for autism screening in elementary aged children. The next steps include further testing to ensure that M-CHAT-S performs well in identifying children with increased likelihood of autism, after which it will be made available to parents, educators, and other professionals.