Abstract
Objective:
Use of intelligence scales in the assessment of children with intellectual disability is of critical importance. Especially, in terms of diagnostic evaluation of these children and preparation of training programs, structure of intelligence scales becomes also very important. The purpose of the present study is to examine construct validity of Wechsler Intelligence Scales for Children (WISC-R) in a sample of children with intellectual disability.
Method:
For this purpose, Exploratory Factor Analysis (EFA) and Confi rmatory Factor Analysis (CFA) were conducted. The sample of the study consisted of 520 children whose Full Scale IQ scores were between 40-79.
Results:
It was found that mean age of children was 10.78 ± 2.69 and mean of Full Scale IQ was 60.34 ± 12.91. The results of EFA revealed that the scale had, as Wechsler reported, two-factor structure. The results of CFA showed that two-factor structure was valid and that values of model fi t indices indicated good fi t [X2 (31, N = 520) = 101.98, X2/sd = 3.29, GFI = .96, AGFI = .93, CFI = .96, RMSEA = .06].
Conclusion:
Considering the widespread use of WISC-R in both clinical practice and academic purposes, it is suggested that for children with intellectual disability, the scores obtained from two-factor model can provide more reliable information.
Keywords: Intellectual (developmental) disability, Wechsler Intelligence Scale for Children-Revised (WISC-R), Confi rmatory Factor Analysis (CFA), Exploratory Factor Analysis (EFA)
