The Wechsler Intelligence Scale for Children-Third Edition (WISC-III) is likely to become the most widely used test of intelligence with deaf children, based on the popularity of the previous versions of the test. Because the test was constructed for hearing children who use spoken English, the following major research questions were asked: (a) Does the WISC-III demonstrate adequate construct validity? and (b) Do specific items exhibit differential item functioning (DIF), and does the nature of the content of each item that exhibits DIF imply that the item is biased? The test was translated into sign language and administered to a total of 110 deaf children at three different sites. The deaf children ranged from ages 8 through 16 (M = 13.25, SD = 2.37), had hearing losses identified as severe or worse, were prelingually deaf, used sign language as their primary means of communication, and were not identified as having any additional handicapping conditions. The sample of deaf children was compared to a sample of 110 hearing children similar in age and Performance IQ. Construct validity was examined using a LISREL multi-sample covariance structure analysis. The covariance structures were different (χ ² (91) = 119.42, p =.024). A Rasch Model was used to detect DIF on the following subtests: Picture Completion, Information, Similarities, Arithmetic, Vocabulary, Comprehension. All of these subtests exhibited DIF, and DIF plus the differences in mean logit ability resulted in numerous items that were more difficult for deaf children on the above Verbal subtests. Item bias was judged by examining the contents of items that exhibited DIF. Items were biased due generally to translation issues and differences in the educational curricula. Thus, deaf children are at a distinct disadvantage when taking these WISC-III subtests. Practitioners are urged to consider these findings when assessing deaf children.

This study proposed to evaluate the appropriateness of selected subtests of the Stanford-Binet Intelligence Scale: Fourth Edition (SB:FE) for use with severely to profoundly hearing impaired children. The subjects used in this study were enrolled in a residential/day school for the deaf whose educational methodology was Total Communication. The subjects were tested on both the SB:FE nonverbal selected subtests and the Performance Scale of the Wechsler Intelligence Scale for Children-Revised (WISC-R PIQ). To assess appropriateness, several procedures were employed comparing data gathered from the hearing impaired sample with data reported for the standardized population of the SB:FE. Correlations were computed between the WISC-R and the SB:FE and comparisons of the total composite scores for each measure were made to detect any systematic differences. The results indicated that the correlations reported for the hearing impaired sample are generally similar to the correlations reported for the standardized sample of the SB:FE. The analysis performed between the Area Scores of the SB:FE and the WISC-R PIQ to detect systematic differences revealed a difference of one standard deviation between these two instruments, with the. SB:FE results being lower than the WISC-R PIQ results. It was concluded that the selected subtests of the SB:FE and the WISC-R PIQ could not be used interchangeably. Further research into this area was advised before using this measure to estimate general cognitive ability for hearing impaired children whose levels of language development may be delayed. Further research was also encouraged to confirm the suggestion of greater predictive validity of the SB:FE with academic measures. It was suggested that these findings indicated that the use of language as a cognitive tool may be important in acquiring certain problem solving skills. / Education, Faculty of / Educational and Counselling Psychology, and Special Education (ECPS), Department of / Graduate

Bibliography / Thesis (M.A.) -- Stellenbosch University, 1988.