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

Concurrent and predictive validities of the Bayley Motor Scale and the Peabody 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.