Early Literacy Research Library (ELRL) - Metric

Baley Scales of Infant and Toddler Development (BSID)


Access: FREE/Open Access

evaluation focus

Child Development (Cognitive, Language, Motor, Social-Emotional, Adaptive Behavior)

applicable ages

0-42 months; 0-3 years

available language(s)



Must be purchased

additional materials

BSID – Summary


The Bayley Scales of Infant and Toddler Development – Third Edition (BISD) is an instrument that can be used to measure a child’s developmental progress and identify developmental delays. It may also aid in teaching parents about their child’s development and planning appropriate interventions.


5 Developmental Subtest/Scales:

    • Cognitive
    • Language (Receptive and Expressive)
    • Motor (Fine and Gross)
    • Social-Emotional
    • Adaptive Behavior (Conceptual, Social, and Practical)

Each subtest/scale involves a series of tasks for the child to complete, ranging from basic (ie tracking an interesting object with their eyes) to complex (ie finding hidden objects).


The Adaptive Behavior scale was adapted from the Parent/Primary Caregiver form of the Adaptive Behavior Assessment System – Second Edition (ABAS-II; Harrison & Oakland, 2003).


Test Observations Measure (additional resource for intervention planning):

    • Growth scores
    • Index scores (standard scores)
    • Subtest scaled scores
    • Percentiles

Administration Format: child-examiner interaction and observation in a series of tasks

Available for Purchase: https://pearsonclinical.in/solutions/bayley-iii/

Source: https://www.academia.edu/50045973/Bayley_Scales_of_Infant_and_Toddler_Development_Third_Edition

Source: https://www.verywellfamily.com/bayley-scales-test-early-development-2162363#:~:text=The%20Bayley%20Scales%20of%20Infant%20and%20Toddler%20Development,examiner%20and%20observations%20in%20a%20series%20of%20tasks.

supporting literature

Balasundaram, P., Avulakunta, I.D. (2022) Bayley Scales of Infant and Toddler Development. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing.
PDF: BSID – 1 – Balasundaram 2022
Link: https://www.ncbi.nlm.nih.gov/books/NBK567715/

Flynn, R.S., Huber, M.D., DeMauro, S.B. (2020) Predictive Value of the BSID-II and the Bayley-III for Early School Age Cognitive Function in Very Preterm Infants. Global Pediatric Health, 7, 1-7.
PDF: BSID – 2 – Flynn 2022
Link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7683841/

Piñon, M. (2010) CHAPTER 1 - Theoretical Background and Structure of the Bayley Scales of Infant and Toddler Development, Third Edition. In: Bayley-III Clinical Use and Interpretation, Practical Resources for the Mental Health Professional. Print, 1-28.
Link: https://www.sciencedirect.com/science/article/abs/pii/B9780123741776100017