Diagnostic implications of McCarthy scale general cognitive index/binet IQ discrepancies for low-socioeconomic-status preschool children

This study compared McCarthy Scale General Cognitive Index (GCI) and Stanford-Binet IQ discrepancies for both normal and handicapped preschool children of low socioeconomic status (SES). Both tests were administered in counter-balanced order to a total of 70 children. The results of these comparisons yielded a significant positive relationship between GCI and IQ, as well as a significant discrepancy between the two scores, favoring IQ, of a relatively small magnitude (3.9 points). There were significant discrepancies favoring IQ for the subgroups of learning-disabled, speech-impaired, and mentally retarded, those for all but mentally retarded being of relatively small magnitude; thus, the learning-disabled group was not uniquely characterized by a large discrepancy. In contrast to results consistently favoring IQ over GCI, when age groups were compared, the younger, 3 year olds, showed the reverse, though nonsignificant, trend.