Cattell -Horn -Carroll (CHC) theory and mean difference in intelligence scores

The use of intellectual and other forms of psychological and mental tests with students who differ culturally, linguistically, or racially is subject to substantial controversy. Professionals responsible for the assessments of culturally different children frequently are uncertain which test instruments provide the most valid, relevant, and equitable results. Research studies indicate mean IQs for some racial/ethnic groups are significantly lower than mean IQs for Caucasians. Some believe IQ differences among racial/ethnic groups suggest the tests unfairly favor one group over another and evidence of group differences indicate intelligence tests are biased against lower performing groups. They further contend intelligence testing influences the disproportionate representation of minority students in special education. Most intelligence test developers currently do not provide information about mean IQ differences by racial/ethnic groups. The Woodcock-Johnson III Cognitive and Achievement Batteries were used to compare the mean score differences of the distributions between African-Americans and Caucasian-Americans. The factor structures of the two groups were also analyzed. In light of the Spearman-Jensen hypothesis and Cattell-Horn-Carroll theory, the mean IQ difference between African-Americans and Caucasian-Americans were hypothesized to be smaller on the Woodcock-Johnson III than on other frequently used measures of intelligence. The results reveal mean IQ differences between Caucasian-Americans and African-Americans are smaller on the Woodcock-Johnson III than on other measures of intelligence. African-Americans obtain lower mean IQs than Caucasian-Americans. The factor structures of the two groups do not differ. Judgments regarding test selection and administration when mean IQ differences occur between two statistically sound instruments will influence educational decision-making and disproportionate representation of minorities in special education. All else being equal, an intelligence test with a smaller disparate mean difference between subgroups is the test that possesses less consequential bias and provides the most relevant and equitable results.