Longitudinal comparisons of wechsler scales in educable mentally handicapped children and adults

The change in IQ scores over an extended period of time (approximately 17 years) of subjects who had been placed in classes for the Educable Mentally Handicapped was investigated. Analysis indicated that a significant difference existed between WISC scores administered at the time of initial placement (mean age, 11–9) and WAIS scores administered at a later date (mean age, 17–6). In addition, although a difference was revealed with respect to WAIS scores when the students were divided into two groups based upon initial WISC scores (⩽70 vs. >70), it was determined that the change was in a uniform fashion over time; i.e., neither regression nor interaction effects were detected. A final analysis revealed that those students who were located for a follow-up testing approximately 10 years later (mean age 28–8) continued to show a significant increase in IQ scores. The importance placed upon IQ scores for initial placement of students in EMH programs appears to remain suspect.     

Predictors of ability-achievement discrepancies in children referred for psychoeducational evaluation

The present study evaluated a school district's psychoeducational screening program to determine the best predictors of two difference score variables: (a) WISC-R FSIQ – PIAT reading recognition score and (b) WISC-R FSIQ – PIAT math score. The study also investigated the merit of using scores from a group-administered achievement test (CAT) as predictors. Subjects were 61 first through fifth graders initially referred for testing from 1982–1984. Multiple regression analyses indicated: (a) for reading, the SIQ score and the PPVT-R – CAT reading difference score were significant predictors, together accounting for 27% of the variance, and (b) for math, the PPVT-R score accounted for 28% of the variance, with additional variables producing nonsignificant increments. Results suggest that CAT scores may prove useful predictors when combined with screening IQ tests to form difference scores.     

An examination of the predictive validity of the keymath diagnostic arithmetic test and the wide range achievement test in exceptional children

Thirty-seven Title I elementary school children were administered the Arithmetic subtest of the Wide Range Achievement Test and the KeyMath Diagnostic Arithmetic Test. One year later, the Metropolitan Achievement Test was administered. While correlations between the Wide Range and the Metropolitan did not reach significance (r =.17), the KeyMath demonstrated a substantial relationship (r -.63). Reasons for such differences in correlations are discussed. It is suggested that the reliability and predictive validity of the KeyMath be extended to different ages and populations.