Concurrent validity of the parent-completed Ages and Stages Questionnaires, 2nd Ed. with the Bayley Scales of Infant Development II in a low-risk sample A. L. Gollenberg,*† C. D. Lynch,‡ L.W. Jackson,§ B. M. McGuinness¶ and M. E. Msall† *Eunice Kennedy Shriver, National Institute of Child Health and Human Development; National Institutes of Health; Department of Health and Human Services; Rockville, MD †University of Chicago Comer Children’s Hospital, Department of Pediatrics, LaRabida Children’s Hospital and JP Kennedy Research Center on Intellectual and Developmental Disabilities; Chicago, IL ‡The Ohio State University College of Public Health, Division of Epidemiology, Columbus, OH §Case Western Reserve University; Department of Epidemiology & Biostatistics; Cleveland, OH ¶State University of New York at Buffalo. Department of Social and Preventive Medicine; Buffalo, NY, USA Accepted for publication 12 August 2009 Keywords child development, developmental screening, diagnostic tests, sensitivity and specificity Correspondence: Audra L. Gollenberg, Epidemiology Branch, Division of Epidemiology, Biostatistics, and Prevention Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, 6100 Executive Boulevard, Room 7B03. Rockville, MD 20892, USA E-mail: gollenba@mail.nih.gov Abstract Background This study assessed the concurrent validity of the Ages and Stages Questionnaire (ASQ) compared with Bayley Scales of Infant Development II (BSID II) amongst children aged 24 months. Methods Data were collected from 53 infants and mothers who participated in the New York State Angler Cohort Child Development Study. Parents completed the 24-month ASQ to assess communication, personal-social, problem-solving ability, and fine and gross motor control.The BSID II was administered by a clinical psychologist at the 24-month home visit for cognitive and psychomotor assessment. The ASQ was scored using age-specific norms of <2 SDs below any domain mean to define failure. A BSID II score of <85 indicated mild or severe delay, while a score of <70 suggested a severe delay. Results Scores on the ASQ communication and personal-social domains were moderately correlated with the BSID II Mental Scale (R = 0.52, P < 0.001; R = 0.45, P < 0.01) and ASQ gross motor with the BSID II Motor Scale (R = 0.46, P < 0.01), whereas ASQ problem-solving and fine motor domains were not significantly correlated with BSID II scores. The ASQ had a sensitivity of 100% and specificity of 87% at 24 months (n = 40) for severely delayed status. Conclusions Results suggest the ASQs provide a simple, valid, and cost-effective method for clinicians and field-based researchers to reduce the number of standardized assessments required to identify developmentally delayed infants at age 24 months. Future studies should further assess the validity of the ASQs in larger, more diverse populations of infants. Background The Bayley Scales of Infant Development (BSID I) and the revised and re-standardized second edition (BSID II) have been heralded as the foremost tests of developmental status in infants (Bayley 1969, 1993). While the Bayley Scales are the most widely used tool to assess infant development, the test is costly, time-consuming, and requires a trained professional for Child: care, health and development Original Article doi:10.1111/j.1365-2214.2009.01041.x © 2009 The Authors Journal compilation © 2009 Blackwell Publishing Ltd 485