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What it measures:

Used to identify children with developmental delay, assist in intervention planning and chart progress; used as a research tool. Assesses 5 domains: cognitive, language, motor, social-emotional, and adaptive. Motor scale includes both a fine motor and a gross motor subtest and can be administered separately to obtain a "motor composite". Social-emotional, and adaptive domains are assessed through a parent questionnaire.

Target Population:

Infants and young children between the ages of 16 d and 42 mo
May be used outside of the age range to describe performance in terms of developmental age (cannot generate norm-referenced scores)

The Bayley-III was standardized on a sample representative of the 2000 US population stratified by age, sex, race/ethnicity, parent educational level, and geographic region.
Clinical cases constituted 9.8% of the Bayley–III normative sample.

It is inappropriate to use the Bayley-III to obtain norm-referenced scores for severely physically or sensory impaired children. The Bayley III should not be used to measure the nature of deficits in a specific skill area.

Accommodations and adaptations may be used and are defined in the manual.

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