Relationship between intelligence and vocabulary

This study explored the correlations of scores on the Wechsler Intelligence Scale for Children-III in screening language problems and scores on the three Comprehensive Receptive and Expressive Vocabulary Test subscales. Participants were 243 students ages 6 to 17 years in Grades K-11 who were identified as learning disabled, learning disabled with speech impairment, mentally retarded, and speech impaired. Analysis indicated strong correlations between the two measures, particularly between the CREVT General Vocabulary and WISC-III Verbal IQ (r = .80), WISC-III Verbal Comprehension Index (r =.83), and the Vocabulary subtest (r =.76). These results held across the grades. Supporting earlier studies of relationships of Verbal IQ and Receptive Vocabulary, correlations were lower between participants in Grades K through 2 than those in higher grades on the WISC-III Verbal IQ and the Receptive Vocabulary subtest. An analysis of the accuracy of the WISC-III for classifying students with language problems indicated improvement in classification over chance. These findings suggest that the WISC-III may be an effective screen for language problems.