Screening for Autism Spectrum Disorder (ASD) in a Naturalistic Home Setting Using the Systematic Observation of Red Flags (SORF) at 18-24 Months

The purpose of the present study is to examine the utility of the Systematic Observation of Red Flags (SORF; Dow et al., 2016) as a level two screener for autism spectrum disorder (ASD) in toddlers when applied to a naturalistic video-recorded home observation. Psychometric properties of the SORF Home were examined in a sample of 228 participants (84 with ASD, 82 developmental delayed, 62 typically developing). Individual items were examined for performance and an algorithm was created with improved sensitivity and specificity, yielding a total Composite score comprised of six items: Poor eye gaze directed to faces, Limited showing and pointing, Limited coordination of nonverbal communication, Less interest in people than objects, Repetitive use of objects, and Excessive interest in particular objects, actions, or activities. Codes indicating clear symptom presence were collapsed to yield a count of the Number of Red Flags (RF). RF scores and Domain totals were also examined for each ASD symptom domain. The Composite provides the briefest measure with optimal performance, while the RF may be preferable for clinicians who are interested in the presence of a full range of clinically significant symptoms. The SORF Home provides a practical alternative to currently available screening methods, demonstrating efficacy when administered by non-experts and applied to a naturalistic setting in a diverse primary care sample.