Concurrent Validity of the Bayley Scales of Infant Development II Motor Scale and the Peabody Developmental Motor Scales in Two-Year-Old Children

Abstract

Concurrent validity of the Bayley Scales of Infant Development, Second Edition (BSID II) Motor Scale and the Peabody Developmental Motor Scales (PDMS) was examined by administering both tests to 38 two-year-old Native American children. A correlation analysis of age equivalent scores indicated very good to high correlation for the BSID II Motor Scale with the PDMS Fine Motor Scale (PDFMS) (r = .87) and the PDMS Gross Motor Scale (PDGMS) (r = .83). A correlation analysis of standard scores showed poor to unacceptable correlation between the BSID II Motor Scale with the PDFMS (r = .64) and the PDGMS (r = .49); further, there was poor agreement between the classifications of significantly delayed, mildly delayed, and within normal limits performance on each test. The PDFMS tended to classify children lower than the BSID II Motor Scale. The scores of the relatively younger children within each of the PDMS 6-month age categories agreed less between the tests than did the scores of the relatively older children. In conclusion, this study provides evidence for the concurrent validity of the BSID II Motor Scale and the PDMS for age equivalent scores, but not for standard scores of 2-year-old children. Professionals must be aware of the strengths and limitations of the BSID II and the PDMS, and choose appropriately to avoid denial of or over-referral for services for young children.