Which of the Three KABC-II Global Scores is the Least Biased?

Abstract

In order to create fairer measures for the assessment of ethnic minority group children, the test authors of the Kaufman Assessment Battery for Children–Second Edition (KABC-II) created three different global indexes: the comprehensive Fluid-Crystallized Index (FCI); the Mental Processing Index (MPI), which excludes subtests that assess crystallized knowledge; and the Nonverbal Index (NVI), which excludes any subtest that requires verbal expression. The test authors encourage clinicians to use the MPI for children with cultural differences and the NVI for children with language differences. The implication is that the FCI is more biased than the MPI and NVI for assessing children from ethnic minorities. However, there has been no empirical evidence to support that hypothesis. Using structural equation modeling, we investigated the predictive validity of the three KABC-II global scores in predicting reading, writing, and math in a nationally representative sample of Caucasian, African-American, and Hispanic school-aged children across three grade groups (1–4, N = 724; 5–8, N = 743; and 9–12, N = 534). Contrary to the test authors’ predictions, the FCI emerged as the fairest predictor of achievement across all age and grade groups. Alternatively, the MPI and NVI showed a persistent intercept overprediction of African-American and Hispanic students’ achievements across grades 5–8. The results provide evidence that more comprehensive global scaled scores might, in fact, be fairer predictor variables than less culturally and linguistically influenced indexes when predicting the achievement of children and adolescents from ethnic minorities.