Applicability of the Wechsler intelligence scale for children
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Date
2002
Authors
Fernando, R.M.S.
Journal Title
Journal ISSN
Volume Title
Publisher
University of Peradeniya
Abstract
The purpose of this study was to translate and adapt the Wechsler Intelligence Scale to assess intelligence in a Sinhala speaking sample of children of Sri Lanka and to develop a preliminary version of the WISC-R, suitable for the cultural conditions of this country. This test belongs to one of the most frequently used intelligence tests in clinical practice (Rispens & Swaab, et aI., 1997). At present no other instrument of the range and calibre of the Wechsler Intelligence Test has been standardized for use in Sri Lanka. The Wechsler Intelligence Test for Children-Revised (WISC-R) and a subsequent revision, the WISC III are one of the most widely used intelligence tests in the world today. As of 1974, twelve foreign translations of the WISC- R were approved and published (Prewitt Diaz & Rodriguez et ai, 1986 ; Dan & Yu et al.,1990). It is currently being used in Asian, European and Latin American countries. Once standardized, this test could be used in educational, research and clinical settings as a research instrument and diagnostic tool. The present study takes the initial steps towards achieving this end. Three studies intended as preliminary steps toward this aim were carried out. The objective of Study I was to ascertain systematically whether a direct translation of the test battery into Sinhala language would yield a distribution of IQ scores comparable to the distribution of Wechsler's normative sample when administered to a sample of Sri Lankan, Sinhala speaking school children. Two age groups equally distributed across gender and three categories of schools were selected for this study. On analyzing the test results of the direct translation, it was found that the means of the Verbal, Performance and Fullscale IQs were significantly different at 0.001 level between Wechsler's mean scores and the Sri Lankan sample for the 11.5 age group, and significantly different at 0.001 level for Performance and Fullscale IQs and at 0.05 level for VerballQ for the 13.5 age group. The aim of Study II was to ascertain which components of the test administered in Study I were consistently difficult for children across a range of age groups and different educational settings. An item analysis of the test results, observations of the researcher and co-tester and the post test interviews were used to obtain this information. The criterion for changing an item was that if 75percent of the children were unable to answer an item it would be considered for adaptation. The rationale for this was that as the items were placed on a graded scale of difficulty, some of the younger children might find it difficult, and reasonably so, to answer the final 25percent of the items. The alternate set of items was developed by a panel of designated persons to replace those shown to be unsuitable for the Sri Lankan Sinhala sample. The substitute items were formulated to suit the socio-cultural conditions of Sri Lanka while trying as much as possible to match the difficulty level of the original item. Study III consisted of administering the adapted version of the WISC-R to a stratified sample of Sinhala speaking school children of the Kandy district. Three age groups distributed equally across gender and the three categories of schools were selected for this study. The scores obtained were compared with the normative scores of Wechsler and also, with those obtained in Study I to find out whether the adaptation had been successful or not. The results showed that some of the IQ categories of Verbal, Performance and Fullscale were significantly different while others were less so, and some were not significantly different. The distribution and pattern of scores in Study III was analyzed and the ensuing problems and shortcomings of the study were examined. Suggestions for future research were also discussed. The problem of cultural differences inherent in an enterprise where a test intended for one culture is given to a different culture comes in to play here. For a test to travel across cultures, some foundational bases must be understood: values, knowing and communication, or else the validity of the test will be in question. Such tests are transportable from one culture to another only with appropriate translation, adaptation and familiar content. When testing across cultures, different assessment methods may be needed to generate a suitable test. To make test interpretation meaningful, one needs to be aware not to make this test slavishly fit with Wechsler's norms of comparing Sri Lankan Children with American norms, but rather a Sri Lankan version of the Wechsler Intelligence Scale for Children, keeping in mind the cultural differences and making meaningful interpretation within these parameters.
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Keywords
Medicine , Intelligence Tests