The Information and Picture Completion Dyad of the WISC-III as a Screening Test for Gifted Referrals

Article excerpt

The study investigated the relationship between Wechsler Intelligence Scale for Children-Third Edition Full Scale IQ scores and subtest dyads from the scale. The Information and Picture Completion dyad correlated with the Full Scale score and acted as an accurate screening instrument for gifted assessment. Although the Information and Picture Completion dyad was not found to be the best predictor of the Full Scale score, it was found to correlate significantly with Full Scale scores. The screening formula was aisle to accurately detect 70 of the 86 referrals (81%). Discriminant analysis revealed that the Picture Completion/Information dyad identified subjects significantly more accurately than the proportional chance criterion. The chosen cutoff sum of scaled scores for combined Picture Completion and Information (26) was found to be the most accurate gifted screen for that dyad.

Psychologists have searched for an accurate way to screen gifted referrals because, ultimately, only half of those nominated qualify for gifted programs (Fineman & Carran, 1986; Gear, 1976). Several studies have found screening instruments to be useful in gifted assessment. Benefits include saved time, money, and effort (Lustberg, Motta, & Naccari, 1990). Kaufman, Ishikuma, and Kaufman-Packer (1991) and Kaufman, Kaufman, Balzopal and McLean (1996) suggest that several factors be included in selecting short forms. These include administration and scoring time as well as psychometric and clinical utility. Fineman & Carran (1986) researched a short form consisting of the Vocabulary, Block Design, and Similarities WISC-R subtests (Wechsler, 1972). When that screening instrument was applied to the records of gifted referrals, 173 of 200 students were accurately identified, a success rate of 87%.

The WISC-III is a recent revision with little research published to date dealing with screening of gifted children. The WISC-III Full Scale Score correlates highly with that of the WISC-R (Sevier, Bain, & Hildman, 1994; Wechsler, 1991). Because of these strong correlations, research conducted on the WISC-R also might be applicable to the WISC-III.

Kaufman et al. (1996) and Sattler (1992) analyzed WISC-III standardization data to select short forms. Although a number of combinations exhibited high reliability, Kaufman et al. (1996) recommended a short form which included the Similarities, Arithmetic, Picture Completion, and Block Design subtests. Kaufman et al. (1996) concluded that this short form represented a compromise of psychometric and clinical soundness and practical utility. Sattler (1992) noted that if speed of administration and ease of scoring were priorities, then Information and Picture Completion represented a dyad worth cautious consideration. Caution is urged because the dyad does not provide as much clinical information as does the Vocabulary-Block Design dyad. An important advantage of the Information-Picture Completion dyad is that standard order of test administration is not disrupted. The Information-Picture Completion dyad also has a high correlation with the Full Scale as shown in Silverstein's (1970) study (r = .889) with the WISC. Therefore, if it is determined that a comprehensive evaluation is needed, the full test can be administered without switching test instruments and without discarding the information already obtained. Individually, Picture Completion was computed to have the second highest correlation to the Full Scale score from the Performance scale, while Information had the second highest correlation from the Verbal Scale (Wechsler, 1991). The present research was conducted to see whether the Information and Picture Completion dyad is an accurate screening device in gifted assessment, and if the linear combination of the Information and Picture Completion subtests is a significant predictor of the Full Scale score.

Method

The data included all children referred for gifted certification since the introduction of the WISC-III in a rural Tennessee school system. …