About the Measure

Domains Omnibus
Subscales Cognitive, Language, motor development and adaptive behaviour
Target Construct Oral language: Receptive and expressive language skills. Social emotional: Communication of needs and self-regulation.
Description Designed to assess the cognitive, language and motor functioning of infants and young children to quickly determine whether a child is progressing according to normal expectations and to determine if future evaluation is needed. When in-depth assessment of cognition, language or motor functioning is needed, the full Bayley-III scales should be used.
Test Authors Bayley, N.
Publisher Pearson (2005)

Implementation details

Respondent Child
Prior knowledge Required Individually administered by speech or occupational therapists, mental health professionals and health practitioners with appropriate Graduate and professional qualifications in their field of practice.
Scoring Complex sets of items a, Scoring requires care to establish norms
Time 30 to 90 minutes
Age 1 month to 42 months

Psychometric details

UK norms YES
Norm / Criterion referenced Norm referenced
Standardisation sample 1700 (221 in UK and Ireland)
Reliability Reliability coefficients ranged from 0.91 to 0.93. Across all ages, average stability coefficients were .80 or higher. )info from web)
Criterion validity Comparison of children’s scores on the Bayley-III and the BSID-II, WPPSI-III, PLS-4, PDMS-2 and ABAS-II Parent/Primary Caregiver Form (ABAS-II-P), all no valid tests. Correlations were only moderate.
Construct validity Test reviews report as insufficient. The Bayley-III cannot be considered a valid test for identifying language disorder/developmental delay and should not be used to identify children with language impairment.
Concurrent validity The highest correlation between the Bayley–III and the WPPSI–III was between the Language composite and the VIQ (r = .83). There is very little difference between the Bayley–III Language composite mean and the WPPSI–III VIQ and FSIQ (98.9, 100.3, and 98.0, respectively).