 Preliminary screening instruments include the Modified Checklist for Autism in Toddlers (M-CHAT), Social Communication Questionnaire (SCQ), and Autism Spectrum Screening Questionnaire (ASSQ).Autism spectrum evaluations are typically conducted by professionals who specialize in developmental disorders, such as psychologists, psychiatrists, or neurologists.Diagnostic instruments that assessing clinicians may use include the Autism Diagnostic Interview-Revised, Autism Diagnostic Observation Schedule, and Childhood Autism Rating Scale, as well as clinical judgment using criteria from the "Diagnostic and Statistical Manual".