Concurrent and Predictive Validities of the Bayley Motor Scale and the Peabody Developmental Motor

Developmental Motor Scales were examined by administering both tests to 23 full-term and 21 healthy premature infants at 12, 15, and 18 months of age. For both groups, a correlation analysis of age-equivalent scores indicated Bayley scores had good to high correlation with Peabody gross motor scores (range, r =.78 to r =.96) and unacceptable correlation with Peabody fine motor scores (range, r =.20 to r =.57). When results were reported using standardized quotients, mean Bayley quotients for the full-term infant group were significantly higher than Peabody gross motor quotients. Prediction of motor development at 18 months of age was limited (range, r =.25 to r =.60), with the exception of Peabody fine motor scores for the premature infant group (r =.75). This study provides evidence of concurrent validity between Bayley motor and Peabody gross motor age-equivalent scores, and it suggests the need for further testing, using separate assessments of gross motor and fine motor ability, to determine motor development at later ages