Abstract
The Revised Denver Developmental Screening Test was compared with the Bayley Scales of Infant Development to investigate the validity of the Denver scale for children under 30 mo. of age. Two groups of infants were studied, referred and nonreferred samples. Correlations of .25 to .52 were obtained between the two measures on the basis of developmental quotients which are significantly lower than those previously reported as mental age estimates. Generally the Denver scale appears to be a conservative test in terms of its classifications, and there is a marked underselection by the Denver test of children who receive abnormal scores on the Bayley scales. There is, however, congruence between the Denver Developmental Quotient and the Bayley Mental Scale score for children of lower ability. While two Denver mental age estimates (personal-social and gross motor) appear congruent with the Bayley? Mental Scale age equivalent, for the most part the Denver test yields significant underestimates of mental age. Over-all the data offer only limited validational support for the use of the Denver test with infants under 2 1/2 yr. of age.