Bayley Assessment Score Revisions in High-risk Population After Release of new Normatives

The Bayley Scales of Infant and Toddler Development, Fourth Edition (Bayley-4), which was released in 2019, received updated normative data in 2023, raising concerns about potential score shifts in previously collected data. This study examined whether developmental interpretations based on the original versus revised norms differ within a cohort of medically complex children.

Scores from 61 children assessed with the Bayley-4 before revised norms were released were used in this study. Frequency of changes in results across Standard Scores at the composite level (cognitive, language, motor) and paired samples t tests of original and new Standard Scores sets were analyzed.

Score changes witnessed went beyond the publisher's descriptions that resulted in increases and decreases throughout several descriptive classifications that are used for clinical interpretation. Of the 3 domains analyzed, language scores showed a minor but statistically significant increase between sample sets ( p < 0.01), whereas motor and cognitive scores showed no significant difference ( p > 0.05). Only 1 change between original and revised scores in the motor domain resulted in a different descriptive classification.

Although many of the revised scores on the Bayley-4 yielded minor differences, unanticipated changes were observed such as score decreases, classification change, and notable differences in mean language scores. Because of these discrepancies, researchers and clinicians using the Bayley-4 during 2019 to 2023 should consider re-evaluating scores.