The Ages and Stages Questionnaires, Third Edition (ASQ-3) was developed for use in pediatric developmental screening to determine the need for further evaluation of developmental delay. 1,2 This screening tool is a system of 21 age-specific questionnaires for children 1 to 66 months of age. 1,2 The ASQ-3 measures 5 developmental domains: gross motor, fine motor, communication, problem-solving, and personal-social, with items rated as typical development, need for monitoring, and need for further assessment. A professional or caregiver can complete the ASQ-3, allowing this tool the potential to be completed by a parent or caregiver before being seen by a clinician. The ASQ-3 has shown to be a reliable and valid instrument for determining the need for further developmental evaluation. The ASQ-3 was found to have excellent test-retest reliability among 4 of the 5 domains measured by the tool. 1,3 This measure has shown to have both excellent interrater reliability 4 and excellent concurrent validity in children >30 months of age. 3 The ASQ-3 has been translated and validated into multiple languages, 5 and studies have shown both the disadvantages 3 and the effectiveness of the measure when translated and culturally adapted for use in various countries. 6,7 This abbreviated summary provides a review of the psychometric properties of the ASQ-3 in pediatric populations. A full review of the ASQ-3 and reviews of nearly 370 other instruments for patients with various health conditions can be found at www.rehabmeasures.org.Please address correspondence to rehabmeasures@ric.org. BIBLIOGRAPHY 1. Squires J, Twombly E, Bricker D, Potter L. Ages and Stages Questionnaires: Third Edition. Baltimore: Paul H. Brookes Publishing; 2009. 2. Halle T, Zaslow M, Wessel J, Moodie S, Darling-Churchill K. Understanding and choosing assessments and developmental screeners for young children: profiles of selected measures. Washington (DC): Office of Planning, Research, and Evaluation, Administration for Children and Families, U.S. Department of Health and Human Services; 2011. 3. Rubio-Codina M, Araujo M, Attanasio O, Muñoz P, Grantham-McGregor S. Concurrent validity and feasibility of short tests currently used to measure early childhood development in large scale studies. PLoS One 2016;11:e0160962. 4. Marks KP, Larosa AC. Understanding developmental-behavioral screening measures. Pediatr Rev 2012;33:448-58. 5. El-Behadil A, Neger E, Perrin E, Sheldrick R. Translations of developmental screening instruments: an evidence map of available research. J Dev Behav Pediatr 2015;36:471-83. 6. Lopes S, Graça P, Teixeira S, Serrano A, Squires J. Psychometric properties and validation of Portuguese version of Ages & Stages Questionnaires (3rd edition): 9, 18 and 30 Questionnaires. Early Hum Dev 2015;91:527-33. 7. Armijo I, Schonhaut L, Cordero M. Validation of the Chilean version of the Ages and Stages Questionnaire (ASQ-CL) in community health settings. Early Hum Dev 2015;91:671-6. 8. King-Dowling S, Rodriguez MC, Missiuna C, Cairney J. Validity of t...