The ADHD Rating Scale-IV is a norm-referenced checklist designed to measure symptoms of attention deficit/hyperactivity disorder (ADHD) according to the diagnostic criteria of the DSM-IV. It includes two subscales: Inattention and Hyperactivity-Impulsivity, and is completed by parents or teachers on a 4-point Likert scale over the past 6 months. The scale is available in both home and school versions, with the home version also available in Spanish. It takes approximately 5 minutes to complete and provides normative data for ages 5 to 18. The scale has been standardized with a sample that closely matches the 1990 U.S. census data in terms of ethnic group and region, but lacks detailed information on socioeconomic status and urban/rural residence. Reliability and validity studies show moderate to high internal consistency and test-retest reliability, but low interrater agreement between parents and teachers. The scale is particularly useful for screening and initial diagnosis but should be used with caution, especially with African American children, due to potential overidentification. It is also valuable for evaluating treatment outcomes using the Reliable Change Index (RCI). Overall, the ADHD Rating Scale-IV is a user-friendly and time-efficient tool for gathering essential information in ADHD referrals, despite its limitations in certain subgroups and settings.The ADHD Rating Scale-IV is a norm-referenced checklist designed to measure symptoms of attention deficit/hyperactivity disorder (ADHD) according to the diagnostic criteria of the DSM-IV. It includes two subscales: Inattention and Hyperactivity-Impulsivity, and is completed by parents or teachers on a 4-point Likert scale over the past 6 months. The scale is available in both home and school versions, with the home version also available in Spanish. It takes approximately 5 minutes to complete and provides normative data for ages 5 to 18. The scale has been standardized with a sample that closely matches the 1990 U.S. census data in terms of ethnic group and region, but lacks detailed information on socioeconomic status and urban/rural residence. Reliability and validity studies show moderate to high internal consistency and test-retest reliability, but low interrater agreement between parents and teachers. The scale is particularly useful for screening and initial diagnosis but should be used with caution, especially with African American children, due to potential overidentification. It is also valuable for evaluating treatment outcomes using the Reliable Change Index (RCI). Overall, the ADHD Rating Scale-IV is a user-friendly and time-efficient tool for gathering essential information in ADHD referrals, despite its limitations in certain subgroups and settings.