Sandra B. Ward

Incremental efficacy of WISC-III factor scores in predicting achievement : What do they tell us ?

Four factors underlie the Full Scale IQ (FSIQ) on the Wechsler Intelligence Scales for Children-Third Edition (WISC-III; D. Wechsler, 1991). Scores from these factors possess greater reliability than individual subtest scores, and some argue that factor scores relate to important phenomena of educational and clinical interest, such as academic achievement and classification status. However, the predictive efficacy of factor scores from the WISC-III relative to the Full Scale IQ (FSIQ) has not been clearly established. This study examined the incremental validity of factor scores from the WISC-III in predicting achievement on the Wechsler Individual Achievement Test (WIAT; Psychological Corporation, 1992). Two groups were evaluated: a nationally representative nonreferred sample (n = 283), and a sample of children referred for evaluation (n = 636). Results indicate that while the factors provide a statistically significant increment, the size of this improvement is generally too small to be of clinical significance for either group. In terms of parsimony and efficiency, the FSIQ is the best predictor of different achievement criteria as measured by the WIAT.

The Incidence and Utility of the ACID, ACIDS, and SCAD Profiles in a Referred Population.

THE ACID, ACIDS, and SCAD profiles are examples of subtest patterns from the WISC-III that have been proposed as potentially helpful in differential diagnosis of exceptionalities. This study investigated the prevalence and utility of these profiles in a large referred population. Although the incidence rates of the ACID and ACIDS profiles in some groups were greater than rates reported for the standardization sample, incidence levels were found to be low in all clinical groups studied. The SCAD profile evidenced generally higher incidence rates but none greater than the rates reported for the standardization sample. The findings support the use of conditional probabilities and incremental gains based on the actual incidence from a referred population to assist in differential diagnosis; however, none of the profiles are recommended as a criterion for determining exceptionality.

Resource Consultation: An Alternative Service Delivery Model for Gifted Education.

Consultation is a collaborative problem‐solving process with the ultimate goal of providing better services to students. Collaboration between specialists in gifted education and general education school personnel is a way to assist teachers meet the special needs of gifted students in the classroom and improve the general education program. A model for consultation to better serve students in gifted education is presented that encourages shared responsibility among school personnel. Implementation of the model is discussed including implications for training of administrators, specialists in gifted education, and general educators.

Possible Criterion-Related Bias of the WISC-III with a Referral Sample

This study examined whether ability scores from the Wechsler Intelligence Scale for Children-Third Edition (WISC-III) showed criterion-related bias. Participants (N= 832) comprised a referral cohort between ages 8 and 16 years that differed by race (Anglo, African American) and gender. Verbal, Performance, and Full Scale IQs from the WISC-III were used to predict Reading, Mathematics, Language, and Writing Composites from the Wechsler Individual Achievement Test (WIAT). Unlike previous research with the WISCIII, 50% of the analyses (12 out of 24) showed statistically significant effects. However, in all instances where bias was found, differences in regressions were statistically significant for intercepts, but not for slopes, and served to overpredict the performance of minority groups (African Americans, females) relative to majority groups (Anglos, males). Results are discussed in the context of how instances of differences in intercepts could mislead psychologists in interpreting childrens ability scores.