Purpose of the Questionnaire (Scale)

The WISC-R is designed to assess the general intellectual ability of children aged 6 to 15 years. It is widely used for educational, clinical, and research evaluations. It targets school-aged children and provides valuable information about their verbal and performance intelligence, assisting in understanding their cognitive potential as well as identifying potential cognitive deficits or learning difficulties. It is used by psychologists, child psychiatrists, special education professionals, and researchers.

Scale Analysis

The original test was developed by David Wechsler and is a revision of earlier versions of the Wechsler Intelligence Scale for Children. The Greek adaptation was conducted by D. Alexopoulos and M. Charitou-Fatouros to reflect the linguistic and cultural characteristics of the Greek population. The test consists of 12 subtests, divided into two main categories: verbal (6 subtests) and performance (6 subtests). The verbal subtests include: Information, Similarities, Arithmetic, Vocabulary, Comprehension, and Digit Span. The performance subtests include: Block Design, Object Assembly, Picture Arrangement, Coding, Symbol Search, and Picture Completion. In the Greek adaptation, substantial modifications were made, including a complete redevelopment of the Vocabulary subtest.

Question Scoring

Scoring follows the guidelines of the official WISC-R manual. Each subtest yields a raw score, which is then converted into a scaled score based on age norms. These scaled scores from the verbal and performance subtests are combined to generate three composite scores: Verbal IQ, Performance IQ, and Full Scale IQ. These indices have a mean of 100 and a standard deviation of 15.

Statistical Analysis

WISC-R scores are normally distributed in the population. Interpretation of results is based on statistical norms. Typically, scores between 90 and 110 are considered average. Scores below 85 may indicate cognitive difficulties, while scores above 115 suggest superior cognitive abilities. The analysis can also focus on individual subtests, offering detailed insights into a child’s cognitive profile (e.g., discrepancies between verbal and performance intelligence).

Validity of the Questionnaire (Scale)

The validity of the Greek version of the WISC-R has been confirmed through studies that show high correlations with other standardized intelligence tests. Specifically, correlations range from 0.72 to 0.79 with the Raven’s Progressive Matrices test and from 0.41 to 0.43 with the Goodenough-Harris Drawing Test. These findings support both the convergent and construct validity of the scale in the Greek population.

Reliability of the Questionnaire (Scale)

The reliability coefficients for the Greek adaptation of the WISC-R are high and range as follows: for the Verbal Scale from 0.74 to 0.92, for the Performance Scale from 0.63 to 0.89, and for the Full Scale from 0.75 to 0.94, depending on the age group. These values confirm the tool’s stability and consistency in administration and re-assessment.

Bibliography

Alexopoulos, D., Charitou-Fatouros, M., Sakas, D., Skaltsas, A., & Vlachou, O. (2000). Reliability and validity of the WISC-R for children aged six to eleven years in Greece. Psychologia, 7(1), 35-45.

Alexopoulos, D. S. (1979). Revision and standardization of the Wechsler Intelligence Scale for Children-Revised (WISC-R) for the age range 13–15 years in Greece. Unpublished PhD Thesis, University College Cardiff.