Bayley-III Scales of Infant and Toddler Development: Transcultural Adaptation and Psychometric Properties

Abstract Scales with evidence of validity and reliability are important to evaluate child development. In Brazil, there is a lack of standardized instruments to evaluate young children. This study investigated the psychometric properties of the Bayley Scales of Infant Development, Third Edition (Bayley-III). It was translated into Brazilian Portuguese, culturally adapted and tested on 207 children (12-42 months of age). Evidence of convergent validity was obtained from correlations of the Bayley-III with the: Peabody Developmental Motor Scale 2, Leiter International Performance Scale-R, Expressive Vocabulary Assessment List and Peabody Picture Vocabulary Test. Exploratory factor analyses showed a single component explaining 86% of the variance, supported by goodness-of-fit indexes in confirmatory factor analysis. The Bailey-III demonstrated good internal consistency with alpha coefficients greater than or equal to .90 and stability for fine motor scale only. These robust psychometric properties support the use of this tool in future national studies on child development.