Bayley Scales of Infant and Toddler Development Third Edition

The Bayley Scales of Infant and Toddler Development, Third Edition (Bayley-III), is an individually administered instrument whose primary purposes are to identify children with developmental delay and to provide information for intervention planning. The Bayley-III assesses infant and toddler development across five domains: Cognitive, Language (Receptive & Expressive), Motor (Gross & Fine), Social-Emotional and Adaptive. Assessment of the former three scales is conducted using items administered to the child. Assessment of the latter two scales relies on primary caregiver responses to a questionnaire.