Department of Psychology, Faculty of Arts, University of Ljubljana, Ljubljana, Slovenia
WISC is one of the best-known and most frequently used intelligence tests for children. The WISC-III version was issued in USA more than a dozen years ago and since then many different language versions of the test were issued in different cultures. When translating the intelligence test from one language and/or cultural milieu to another, it is essential that the process of translation and adaptation considers the same methodological design as it was used in building the original version. All requirements about comparability of the original and adapted version in the theoretical structure and the construct validity are also to be met. The structure of the Slovene version, on the normative sample of 1.080 children, and 13 other language versions, with the total number of almost 16.000 children, from the cross-cultural study [Georgas, J., Weiss, L.G., van de Vijver, F.J.R & Saklofske, D.H. (2003). Culture and children's intelligence: Cross-cultural analysis of the WISC-III. San Diego: Academic Press.], was being studied. The purpose of the analysis of structural equivalence was to determine to what extent the construct of intelligence as measured by WISC-III is similar across the cultures. Exploratory and confirmatory factor analyses tested the four-factor solution (Verbal Comprehension, Processing Speed, Perceptual Organization, Freedom of Distractibility) stressing the stability of the last factor.
The WISC was and still is one of the best-known and most frequently used individually administered instruments for assessing cognitive abilities in children (6-17 years). It was introduced (along with WPPSI and WAIS) by David Wechsler about seventy years ago (Wechsler, 1939). There was no firm cognitive theory behind the idea of testing intelligence, he merely conceptualized intelligence ”... as an aggregate and global entity; the capacity of the individual to act purposefully, to think rationally and to deal effectively with his/her environment.” (Wechsler, 1944). But intelligence is not only equal to a sum of these capabilities –it joins them into a whole. Wechsler also claimed that one must count on a number of so-called “non-intellectual” factors when assessing intelligence. Hidden in the Wechsler’s tests there was an interesting scheme of a multidimensional structure of intelligence and the idea about a test series. Items of dissimilar difficulties in tasks provoking different cognitive performances were “packed” into different tests (WPPSI for 4 to 8, WISC from 6 to 17 and WAIS from 15 to 99 years of age) in order to obtain the comparable results in standardized IQ points for same person through different ages, for different persons at the same age and even for different persons through different ages (Humphreys, 1989; Kaufman, 1990; Wechsler, 1944).
WISC-III was published in the United States in 1991, following five years of research and development by staff at The Psychological Corporation (Wechsler, 1991). The primary reason for this project was to update the WISC-R norms published in 1974. Based on longitudinal data of cognitive functioning across time, Flynn (1984, 1987, 1999) found that in several countries cognitive scores increased significantly in a single generation. Thus, it is considered important to update norms periodically so that children’s intelligence is assessed relative to a contemporary cohort. The United Kingdom version of WISC-III was carried out a year later (Banas, 1993; Wechsler, 1992).
In addition to updating the norms, each revision incorporates recent advances in understanding of cognitive ability. For example, the WISC-III included enhancements made to the working memory and speed of information processing constructs with the addition of the new Symbol Search subtest and the resultant...