Exploratory and Confirmatory Factor Analysis of the Universal Nonverbal Intelligence Test-Second Edition: Testing Dimensionality and Invariance Across Age, Gender, Race, and Ethnicity.

This study examined key assumptions underlying the interpretation of one of the most widely used multidimensional nonverbal tests of intelligence, the Universal Nonverbal Intelligence Test-Second Edition (UNIT2). Specifically, we examined the dimensionality of the UNIT2 and the interpretive relevance of its factors. We also examined the invariance of constructs measured by the UNIT2 across age groups, gender, race, and ethnicity. Structural analyses were conducted using data from 1,802 individuals aged 5 to 21 years who participated in the norming of the UNIT2. Results indicate that the UNIT2 is primarily a measure of psychometric g. Tests of invariance indicate that the factors measured by the UNIT2 are calibrated differently across age, gender, and racial groups. The Memory, Quantitative, and Reasoning factors represent psychometric g quite well. However, there is insufficient unique, reliable variance for the interpretation of the index scores reflecting the Memory, Quantitative, and Reasoning factors. Based on the results of this study, we question whether the administration of multidimensional nonverbal tests of intelligence is worth the time and effort when unidimensional tests may provide the same information.