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NDACAN Measure Details

Bayley Scales of Infant Development-II


Long the standard of excellence for evaluating the development of young children, the Bayley Scales of Infant Development®—Second Edition (BSID–II) offers a standardized assessment of cognitive and motor development for children ages 1 month through 42 months. BSID–II incorporates technical soundness, expanded content coverage, enhanced clinical validity, and brighter stimulus materials. It reflects current norms and allows diagnostic assessment at an earlier age to help lead to needed intervention. BSID–II was renormed on a stratified random sample of 1,700 children (850 boys and 850 girls) ages one month to 42 months, grouped at one-month to three-month intervals on the variables of age, sex, region, race/ethnicity, and parental education. You can more accurately compare a child's performance to a contemporary reference group. BSID–II includes information about clinical samples. Data are provided in the Manual for the following groups: children who were born prematurely, have the HIV antibody, were prenatally drug exposed, were asphyxiated at birth, are developmentally delayed or have frequent otitis media, are autistic, or have Down's syndrome. More than 100 new items were created to apply to the expanded age range. The Behavior Rating Scale (formerly the Infant Behavior Record) also was revised in both structure and content to reflect more relevant dimensions of test-taking behavior. BSID–II retains the broad content coverage that characterized the original scales, and includes the Mental Scale, the Motor Scale, and the Behavior Rating Scale. Mental Scale yields a normalized standard score called the Mental Development Index, evaluating a variety of abilities: sensory/perceptual acuities, discriminations, and response; acquisition of object constancy; memory, learning, and problem solving; vocalization, beginning of verbal communication; basis of abstract thinking; habituation; mental mapping; complex language; and mathematical concept formation. Motor Scale assesses these skills: degree of body control, large muscle coordination, finer manipulatory skills of the hands and fingers, dynamic movement, dynamic praxis, postural imitation, and stereognosis. Behavior Rating Scale provides information that should be used to supplement information gained from the Mental and Motor scales. The 30-item scale rates the child's relevant test-taking behaviors and measures the following factors: attention/arousal, orientation/engagement, emotional regulation, and motor quality.


Black, M. M. & Matula, K. (1993). Bayley Scales of Infant Development®—Second Edition (BSID–II). San Antonio, TX: Pearson Education, Inc. Retrieved from: