The Attention Deficit Disorder Evaluation Scale-Fifth Edition (ADDES-5) enables educators, school and private psychologists, paediatricians, and other medical personnel to evaluate Attention-Deficit/Hyperactivity Disorder in children and youth from input provided by primary observers of the student’s behaviour. The ADDES-5 was developed from research in behaviour disorders, learning disabilities, and Attention-Deficit/Hyperactivity Disorder; current literature in psychology, neurology, and education; and current DSM-5™ practices in identification and diagnosis. The subscales, Inattentive and Hyperactive-Impulsive, are based on the current characteristics of ADHD. The results provided by the scale are commensurate with criteria used by educational, psychiatric, and pediatric professionals to identify Attention-Deficit/Hyperactivity Disorder in children and youth. The scale is available in two versions: School Version, a reporting form for educators, and Home Version, a reporting form for parents.